History of NATO in Timeline

NATO is a military alliance formed in 1949 by North American and European countries to provide collective security. Its core principle, enshrined in Article 5 of the North Atlantic Treaty, is that an attack on one member is considered an attack on all, obligating mutual defense. Founded post-World War II, it aims to safeguard the freedom and security of its members through political and military means.

1941: Atlantic Charter Agreement

In 1941, the Atlantic Charter, an agreement between the United States and the United Kingdom, laid out a framework for international cooperation without territorial expansion after World War II.

March 1947: Treaty of Dunkirk Signed

In March 1947, the Treaty of Dunkirk was signed by France and the United Kingdom as a Treaty of Alliance and Mutual Assistance in the event of possible attacks by Germany.

February 1948: Talks for a wider military alliance began

In February 1948, talks for a wider military alliance, which could include North America, began in the United States, where their foreign policy under the Truman Doctrine promoted international solidarity against actions they saw as communist aggression, such as the coup d'état in Czechoslovakia.

March 1948: Treaty of Brussels Signed

In March 1948, the alliance established by the Treaty of Dunkirk was expanded in the Treaty of Brussels to include the Benelux countries, forming the Brussels Treaty Organization, commonly known as the Western Union.

April 1949: Establishment of NATO

On April 4, 1949, NATO was established with the signing of the North Atlantic Treaty (Washington Treaty). The 12 founding members were Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the United States.

April 1949: Signature of the North Atlantic Treaty

On April 4, 1949, the North Atlantic Treaty was signed by the member states of the Western Union plus the United States, Canada, Portugal, Italy, Norway, Denmark, and Iceland, marking a crucial step in the formation of NATO.

1949: North Atlantic Treaty Signed

In 1949, NATO was established with the signing of the North Atlantic Treaty. This treaty established a system of collective security among member states, agreeing to mutual defense in response to an attack by an outside party, as enshrined in Article 5.

1949: Original NATO Members

In 1949, twelve original members joined NATO. These founding members were Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the United States.

1951: Formation of SHAPE

In 1951, Supreme Headquarters Allied Powers Europe (SHAPE) was formed, adopting many of the Western Union's military structures and plans, including agreements on standardizing equipment and stationing foreign military forces in European countries.

1952: Greece and Turkey Join NATO

In 1952, Greece and Turkey became members of NATO.

1952: Establishment of Secretary General and First Maritime Exercises

In 1952, the post of Secretary General of NATO was established as the organization's chief civilian. Also, that year marked the first major NATO maritime exercises, Exercise Mainbrace, and the accession of Greece and Turkey to the organization.

May 1955: West Germany Joins NATO

In May 1955, West Germany was permitted to rearm militarily and joined NATO, which was a major factor in the creation of the Soviet-dominated Warsaw Pact.

1955: West Germany Joins NATO

In 1955, West Germany joined NATO.

1955: Warsaw Pact Formed

In 1955, the Warsaw Pact was formed by the Soviet Union and its satellite states as a rival to NATO during the Cold War.

1961: Building of the Berlin Wall

In 1961, the building of the Berlin Wall marked a height in Cold War tensions, when 400,000 US troops were stationed in Europe.

July 1962: French Algeria Independence

In July 1962, French Algeria gained its independence and was no longer covered under Article 5 of the North Atlantic Treaty.

1966: France Withdraws from NATO's Military Structure

In 1966, doubts over the credibility of NATO's defence led to the development of the independent French nuclear deterrent and the withdrawal of France from NATO's military structure.

1982: Treaty of Lisbon - Article 42(7)

Article 42(7) of the 1982 Treaty of Lisbon specifies that "If a Member State is the victim of armed aggression on its territory, the other Member States shall have towards it an obligation of aid and assistance by all the means in their power".

1982: Spain Joins NATO

In 1982, Spain became a member of NATO.

1989: Revolutions of 1989 in Europe

The Revolutions of 1989 in Europe led to a strategic re-evaluation of NATO's purpose, nature, tasks, and focus on the continent.

October 1990: East Germany Joins the Federal Republic of Germany and NATO

In October 1990, East Germany became part of the Federal Republic of Germany and the alliance.

November 1990: Treaty on Conventional Armed Forces in Europe Signed

In November 1990, the alliance signed the Treaty on Conventional Armed Forces in Europe (CFE) in Paris with the Soviet Union, mandating specific military reductions across the continent.

1990: Operation Anchor Guard

Following the end of the Cold War, the first operations, Anchor Guard in 1990, were prompted by the Iraqi invasion of Kuwait. Airborne early warning aircraft were sent to provide coverage of southeastern Turkey.

1990: Political Dialogue with Japan Begins

In 1990, political dialogue with Japan began, initiating increased contact between NATO and countries outside its cooperation initiatives.

1990: East Germany Added to NATO

In 1990, with the reunification of Germany, the territory of the former East Germany was added to NATO.

February 1991: Collapse of the Warsaw Pact

In February 1991, the collapse of the Warsaw Pact removed the de facto main adversaries of NATO.

1991: Dissolution of the Soviet Union

Following the dissolution of the Soviet Union in 1991, NATO adapted its role and focus.

1991: Operation Ace Guard

Following the end of the Cold War, the operation Ace Guard in 1991, were prompted by the Iraqi invasion of Kuwait. A quick-reaction force was deployed to the area.

October 1992: UN Security Council Resolution 816

In October 1992, the deteriorating situation in Bosnia led to United Nations Security Council Resolution 816, authorizing member-states to enforce a no-fly zone over central Bosnia and Herzegovina.

1992: Military Interventions in Bosnia and Herzegovina

In 1992, NATO conducted its first major military interventions in Bosnia and Herzegovina.

1992: Military Interventions in Bosnia

In the 1990s, during the breakup of Yugoslavia, NATO conducted its first military interventions in Bosnia from 1992.

April 1993: Start of Operation Deny Flight

On 12 April 1993, NATO complied with UN Security Council Resolution 816 and started enforcing the ban with Operation Deny Flight.

June 1993: Start of Operation Sharp Guard

From June 1993, Operation Sharp Guard added maritime enforcement of the arms embargo and economic sanctions against the Federal Republic of Yugoslavia.

February 1994: First Wartime Action

On 28 February 1994, NATO took its first wartime action by shooting down four Bosnian Serb aircraft violating the no-fly zone.

April 1994: Air Strikes near Goražde and Hostage Situation

On 10 and 11 April 1994, the United Nations Protection Force called in air strikes to protect the Goražde safe area, resulting in the bombing of a Bosnian Serb military command outpost near Goražde by two US F-16 jets acting under NATO direction. In retaliation, Serbs took 150 U.N. personnel hostage on 14 April. On 16 April a British Sea Harrier was shot down over Goražde by Serb forces.

1994: Partnership for Peace and Mediterranean Dialogue Initiative

In 1994, diplomatic forums for regional cooperation between NATO and its neighbours were set up, including the Partnership for Peace and the Mediterranean Dialogue initiative during this post-Cold War period.

1994: Establishment of Mediterranean Dialogue

In 1994, the Mediterranean Dialogue was established to coordinate with Israel and countries in North Africa.

1994: Establishment of Partnership for Peace Programme

In 1994, the Partnership for Peace (PfP) programme was established, based on individual bilateral relations between each partner country and NATO.

August 1995: Operation Deliberate Force

In August 1995, a two-week NATO bombing campaign, Operation Deliberate Force, began against the Army of the Republika Srpska, after the Srebrenica genocide.

November 1995: Dayton Agreement

In November 1995, NATO air strikes helped bring the Yugoslav Wars to an end, resulting in the Dayton Agreement.

1995: Military Interventions in Bosnia and Herzegovina

In 1995, NATO conducted major military interventions in Bosnia and Herzegovina.

1995: Military Interventions in Bosnia

In the 1990s, during the breakup of Yugoslavia, NATO conducted its first military interventions in Bosnia to 1995.

October 1996: End of Operation Sharp Guard

Operation Sharp Guard ran until October 1996, adding maritime enforcement of the arms embargo and economic sanctions against the Federal Republic of Yugoslavia.

December 1996: Start of Operation Joint Endeavor / IFOR

In December 1996, NATO deployed a UN-mandated peacekeeping force, under Operation Joint Endeavor, named IFOR.

May 1997: Establishment of Euro-Atlantic Partnership Council

On 29 May 1997, the Euro-Atlantic Partnership Council (EAPC) was first established as a forum for regular coordination, consultation and dialogue between all fifty participants.

1997: Euro-Atlantic Partnership Council

In 1997, the Euro-Atlantic Partnership Council was established as one of the diplomatic forums for regional cooperation between NATO and its neighbours.

September 1998: UN Security Council Resolution 1199

In September 1998, in an effort to stop Slobodan Milošević's Serbian-led crackdown on KLA separatists and Albanian civilians in Kosovo, the United Nations Security Council passed Resolution 1199 to demand a ceasefire.

1998: NATO Establishes General Guidelines for Cooperation

In 1998, NATO established a set of general guidelines that do not allow for a formal institutionalization of relations, but reflect the Allies' desire to increase cooperation.

1998: NATO–Russia Permanent Joint Council

In 1998, the NATO–Russia Permanent Joint Council was created as one of the diplomatic forums for regional cooperation between NATO and its neighbours.

March 1999: NATO starts bombing campaign

In March 1999, negotiations broke down, and NATO initiated a 78-day bombing campaign, called Operation Allied Force, targeting the Federal Republic of Yugoslavia's military capabilities to protect regional security.

April 1999: NATO adopts Alliance Strategic Concept

In April 1999, recognizing the post-Cold War military environment, NATO adopted the Alliance Strategic Concept during its Washington summit, emphasizing conflict prevention and crisis management.

June 1999: Milošević Accepts Peace Plan and UN Resolution

In June 1999, Milošević accepted an international peace plan, ending the Kosovo War, and accepted UN resolution 1244, leading to NATO establishing the KFOR peacekeeping force to protect humanitarian missions and deter violence.

1999: Hungary, Poland, and Czech Republic Join NATO

At the 1999 Washington summit, Hungary, Poland, and the Czech Republic officially joined NATO, and NATO issued new guidelines for membership, with individualized "Membership Action Plans".

1999: Military Interventions in Yugoslavia

In 1999, NATO conducted major military interventions in Yugoslavia.

2000: Term "Contact Countries" Agreed by Allies

Following extensive debate, the term "Contact Countries" was agreed by the Allies in 2000.

September 2001: Operation Essential Harvest mounted

In August-September 2001, NATO mounted Operation Essential Harvest, a mission disarming ethnic Albanian militias in the Republic of Macedonia.

October 2001: NATO invokes Article 5 following 9/11 attacks

In October 2001, following the September 11 attacks in the United States, NATO invoked Article 5 of the NATO Charter for the first time. NATO also confirmed the attacks were eligible under the terms of the North Atlantic Treaty and began Operation Active Endeavour in the Mediterranean Sea.

December 2002: Berlin Plus Agreement Signed

On 16 December 2002, the European Union (EU) signed a comprehensive package of arrangements with NATO under the Berlin Plus agreement. This agreement allowed the EU to use NATO assets under certain conditions.

2002: NATO-Ukraine Action Plan

In 2002, Ukraine's relationship with NATO began with the NATO–Ukraine Action Plan.

April 2003: NATO agrees to take command of ISAF

In April 2003, NATO agreed to take command of the International Security Assistance Force (ISAF).

October 2003: UN authorizes ISAF mission expansion throughout Afghanistan

In October 2003, the UN Security Council authorized the expansion of the ISAF mission throughout Afghanistan.

2003: Turkey invokes Article 4 at start of Iraq War

In 2003, Turkey invoked the first Article 4 meetings at the start of the Iraq War.

August 2004: NATO forms Training Mission in Iraq

In August 2004, during the Iraq War, NATO formed the NATO Training Mission – Iraq to assist the Iraqi security forces.

December 2004: End of SFOR and Transition to EU Force Althea

In December 2004, SFOR ended and operations were then passed onto the European Union Force Althea.

2004: Seven New Members Join NATO

In 2004, Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia, and Slovenia joined NATO.

2004: Announcement of Istanbul Cooperation Initiative

In 2004, the Istanbul Cooperation Initiative was announced as a dialogue forum for the Middle East, similar to the Mediterranean Dialogue.

2005: Putin's Statement on Ukraine Joining NATO

In 2005, Russian president Vladimir Putin stated that if Ukraine joined NATO, Russia would respect their choice, considering it their sovereign right.

July 2006: ISAF takes over military operations in southern Afghanistan

On July 31, 2006, the ISAF took over military operations in the south of Afghanistan from a US-led anti-terrorism coalition.

2006: NATO Enlargement and Democratic Consolidation

A 2006 study in the journal Security Studies argued that NATO enlargement contributed to democratic consolidation in Central and Eastern Europe.

2006: 2% GDP Defense Spending Goal

Since 2006, the goal has been for each country to spend at least 2 percent of its gross domestic product on its own defense.

2007: Putin Opposes NATO Enlargement

Since his 2007 Munich speech, Vladimir Putin has strongly opposed further NATO enlargement.

2007: Election of Nicolas Sarkozy

The election of French president Nicolas Sarkozy in 2007 led to a major reform of France's military position.

2008: Georgia Promised Future Membership

During the 2008 summit in Bucharest, Georgia was promised "future membership" in NATO.

2008: UN calls for protection of Operation Allied Provider ships

In 2008, the United Nations Secretary-General called on member-states to protect the ships of Operation Allied Provider, which was distributing aid as part of the World Food Programme mission in Somalia.

April 2009: France Returns to Full NATO Membership

On April 4, 2009, France returned to full NATO membership, including rejoining the NATO Military Command Structure, while maintaining an independent nuclear deterrent.

August 2009: NATO deploys warships to protect maritime traffic from Somali pirates

Beginning on August 17, 2009, NATO deployed warships in an operation to protect maritime traffic in the Gulf of Aden and the Indian Ocean from Somali pirates, and help strengthen the navies and coast guards of regional states.

2009: Albania and Croatia Join NATO

In 2009, Albania and Croatia became members of NATO.

2009: France Returns to Integrated Military Command

In 2009, Nicolas Sarkozy negotiated France's return to NATO's integrated military command and the Defence Planning Committee.

2010: Ukraine Renounces NATO Aspirations

In 2010, under President Viktor Yanukovych, Ukraine re-affirmed its non-aligned status and renounced aspirations of joining NATO.

March 2011: UN Security Council authorizes military action in Libya

In March 2011, violence in Libya led to United Nations Security Council Resolution 1973, which authorized military action to protect civilians and enforce a ceasefire.

March 2011: NATO states agree to enforce arms embargo against Libya

On March 20, 2011, NATO states agreed on enforcing an arms embargo against Libya with Operation Unified Protector, monitoring and interdicting vessels suspected of carrying illegal arms or mercenaries.

March 2011: NATO agrees to take control of Libyan no-fly zone

On March 24, 2011, NATO agreed to take control of the no-fly zone over Libya from the initial coalition, enforcing the UN resolution with assistance from Qatar and the United Arab Emirates. Command of targeting ground units remained with the coalition's forces.

October 2011: NATO mission in Libya ends

By the end of the mission in October 2011, after the death of Colonel Gaddafi, NATO planes had flown about 9,500 strike sorties against pro-Gaddafi targets.

December 2011: NATO Training Mission in Iraq concludes

On December 17, 2011, the NATO Training Mission-Iraq officially concluded.

2011: France reinforces ISAF efforts in Afghanistan

In 2011, France allowed a squadron of Mirage 2000 fighter/attack aircraft to be moved to Kandahar to reinforce the ISAF's efforts in Afghanistan.

2011: Intervention in Libya

In 2011, NATO was involved in intervention in Libya.

April 2012: Turkish PM considers invoking Article 5

In April 2012, Turkish Prime Minister Recep Tayyip Erdoğan considered invoking Article 5 of the NATO treaty due to the Syrian civil war, prompting a quick response from the alliance.

May 2012: Human Rights Watch reports civilian deaths in Libya campaign

A report from the organization Human Rights Watch in May 2012 identified at least 72 civilians killed in the NATO campaign in Libya.

June 2012: Shooting down of a Turkish military jet by Syria

After the shooting down of a Turkish military jet by Syria in June 2012 NATO approved Operation Active Fence.

October 2012: Syrian forces shell Turkish cities

In October 2012 Syrian forces shelling Turkish cities resulting in two Article 4 consultations, NATO approved Operation Active Fence.

2012: Expansion of Global Partners Group

By 2012, the Alliance had broadened the group of "Contact Countries", referring to them as "global partners" or "partners across the globe", to discuss issues such as counter-piracy and technology exchange.

2012: NATO endorses plan to end Afghanistan war

During its 2012 Chicago Summit, NATO endorsed a plan to end the Afghanistan war and remove the NATO-led ISAF Forces by the end of December 2014.

2012: Turkey invokes Article 4 twice during Syrian Civil War

In 2012, Turkey invoked Article 4 twice during the Syrian civil war, after the downing of an unarmed Turkish F-4 reconnaissance jet, and after a mortar was fired at Turkey from Syria.

October 2013: Libyan PM requests NATO assistance

In October 2013, following a coup d'état attempt, Libyan Prime Minister Ali Zeidan requested technical advice and trainers from NATO to assist with ongoing security issues.

December 2014: ISAF disestablished in Afghanistan

In December 2014, ISAF was disestablished in Afghanistan and replaced by the follow-on training Resolute Support Mission.

December 2014: Ukraine Ends Non-Aligned Status

In December 2014, Ukraine's parliament voted to end its non-aligned status following Russia's occupation of Crimea and support for separatists in eastern Ukraine.

2014: Obama's Statement on Georgia's Membership Path

In 2014, US President Barack Obama stated that Georgia was not "currently on a path" to NATO membership.

2014: NATO Declaration on Defense Spending

In 2014, a NATO declaration stated that countries not meeting the 2 percent defense spending goal would "aim to move towards the 2 percent guideline within a decade".

2014: Russian Annexation of Crimea and Invocation of Article 4

In 2014, the Russian annexation of Crimea led to strong condemnation by all NATO members, and was one of the seven times that Article 4, which calls for consultation among NATO members, has been invoked.

2014: Russian Annexation of Crimea

In 2014, the Russian annexation of Crimea prompted strong condemnation from NATO and a renewed focus on collective defence.

2015: Decline in Military Spending

From 1990 to 2015, military spending by NATO's European members declined by 28 percent.

2015: Turkey invokes Article 4 after ISIL threats

In 2015, Turkey invoked Article 4 again after threats by Islamic State of Iraq and the Levant to its territorial integrity.

2015: Turkey calls for emergency meeting after Suruç bombing

In response to the 2015 Suruç bombing, which Turkey attributed to ISIS, and other security issues along its southern border, Turkey called for an emergency meeting.

June 2016: Russian Perception of NATO Threat

A June 2016 Levada Center poll found that 68 percent of Russians think that deploying NATO troops in the Baltic states and Poland is a threat to Russia.

2016: Creation of NATO Enhanced Forward Presence

At the 2016 Warsaw summit, NATO countries agreed on the creation of NATO Enhanced Forward Presence, which deployed four multinational battalion-sized battlegroups in Estonia, Latvia, Lithuania, and Poland.

2017: Montenegro Joins NATO

In 2017, Montenegro joined NATO.

2017: Polish Perception of Russian Threat

In 2017, a Pew Research Center report indicated that 65 percent of Poles surveyed identified Russia as a "major threat".

January 2018: Qatar and NATO Sign Joint Security Agreement

In January 2018, Qatar and NATO signed a joint security agreement.

June 2018: Qatar's Wish to Join NATO Denied

In June 2018, Qatar expressed a wish to join NATO, but it was ruled out as only additional European countries could join according to Article 10 of NATO's founding treaty.

2018: Polish Support for US Forces in Poland

In 2018, 67 percent of Poles surveyed favored US forces being based in Poland.

2019: Ukraine Enshrines NATO Membership Goal

In 2019, Ukraine enshrined the goal of NATO membership in the Constitution.

February 2020: Article 4 consultation due to tensions in Syria

In February 2020, an Article 4 consultation happened due to increasing tensions during the Northwestern Syria offensive, risking direct confrontation between Russia and a NATO member.

2020: North Macedonia Joins NATO

In 2020, North Macedonia became a member of NATO.

April 2021: NATO agrees to withdraw troops from Afghanistan

In April 2021, NATO agreed to start withdrawing its troops from Afghanistan by May 1.

June 2021: NATO Affirms Ukraine's Future Membership

At the June 2021 Brussels Summit, NATO leaders affirmed that Ukraine would eventually join NATO, supporting Ukraine's right to self-determination.

August 2021: Taliban encircles Kabul

By August 15, 2021, the Taliban controlled most of Afghanistan and had encircled Kabul, leading some politicians to describe the withdrawal of Western troops as NATO's greatest debacle since its founding.

March 2022: Extraordinary Summit in Brussels and Activation of NATO Response Force

In March 2022, NATO leaders met at Brussels for an extraordinary summit which also involved Group of Seven and European Union leaders. NATO member states agreed to establish four additional battlegroups in Bulgaria, Hungary, Romania, and Slovakia, and elements of the NATO Response Force were activated for the first time in NATO's history.

June 2022: Deployment of Troops Along Eastern Flank

As of June 2022, NATO had deployed 40,000 troops along its Eastern flank to deter Russian aggression. To supplement Bulgaria's Air Force, Spain sent Eurofighter Typhoons, the Netherlands sent eight F-35 attack aircraft, and additional French and US attack aircraft would arrive soon as well.

July 2022: NATO Estimate of Members Meeting Defense Target

In July 2022, NATO estimated that 11 members would meet the target in 2023 of spending at least 2 percent of their GDP on defense.

September 2022: Ukraine Applies for NATO Membership

In September 2022, Ukraine applied for NATO membership after Russia proclaimed it had annexed the country's southeast.

2022: Russian Invasion of Ukraine

In 2022, the Russian invasion of Ukraine led to a major reinforcement of NATO's eastern flank and caused Finland and Sweden to abandon their neutral status and join the alliance.

2023: KFOR soldiers continue to operate in Kosovo

As of 2023, around 4,500 KFOR soldiers, representing 27 countries, continue to operate in the Kosovo area.

2023: Finland Joins NATO

In 2023, spurred by the Russo-Ukrainian war, Finland became a member of NATO.

2023: Biggest Contributors to NATO Budget

In 2023, the United States and Germany were the biggest contributors to the NATO budget, each at 16.2%.

2023: Estimated Number of NATO Members Meeting 2% Defense Spending Target

In July 2022, NATO estimated that 11 members would meet the 2% spending target in 2023.

February 2024: Stoltenberg Announces Increased Defense Spending

On 14 February 2024, NATO Secretary General Jens Stoltenberg said that 18 member states would meet the 2% target in 2024.

June 2024: Record Number of NATO Members Meeting Defense Spending Targets

On 17 June 2024, prior to the 2024 Washington summit, Jens Stoltenberg announced that a record 23 of 32 NATO member states were meeting their defense spending targets of 2% of their country's GDP. NATO added that defense spending for European member states and Canada was up 18% in the past year alone.

2024: Commitment to Spend 2% of GDP on Defence

At the 2014 Wales summit, the leaders of NATO's member states formally committed to spend the equivalent of at least two percent of their gross domestic products on defence by 2024.

2024: Sweden Joins NATO

In 2024, spurred by the Russo-Ukrainian war, Sweden became a member of NATO.

2024: Biggest Contributors to NATO Budget

In 2024, the United States and Germany were the biggest contributors to the NATO budget, each at 16.2%.

2024: US Threats to Canada and Denmark

Since 2024, NATO faced an unprecedented rift between the United States and the majority of other NATO members, as US president Donald Trump repeatedly threatened the sovereignty of two founding members, Canada and Denmark.

2024: Internal Crisis due to US Threats

Since 2024, NATO has entered a period of internal crisis due to threats made by the United States against the sovereignty of two founding NATO members Canada and Denmark.

September 2025: Operation Eastern Sentry launched

In September 2025, Operation Eastern Sentry was launched in response to Russian drone incursions into Polish airspace, aiming to strengthen NATO's eastern flank.