From Foe to Friend: 15 Countries That Overcame National Rivalries in History - History Collection

9. Greece and Turkey

Despite military confrontations and territorial disputes, Greece and Turkey have experienced periods of rapprochement. The 1999 earthquakes in both countries led to mutual humanitarian assistance, initiating “earthquake diplomacy” that improved relations. In 2023, following a devastating earthquake in Turkey, Greece was among the first to offer aid, sending rescue teams and supplies. This swift response contributed to a renewed commitment to dialogue and cooperation, focusing on regional stability and mutual interests (aljazeera.com).

10. United States and Japan

From enemy combatants in World War II to strategic allies, the U.S.-Japan relationship has evolved into a cornerstone of Asia-Pacific security. The 1960 Treaty of Mutual Cooperation and Security established a framework for defense collaboration, while the 1997 Guidelines for U.S.-Japan Defense Cooperation expanded bilateral military coordination. In 2015, Japan reinterpreted its pacifist constitution, allowing for collective security measures. The alliance has been further strengthened through joint military exercises, intelligence sharing, and cooperation on regional security challenges, underscoring a shared commitment to peace and stability (cfr.org).

11. Poland and Lithuania

Historical grievances—most notably border disputes—strained Poland-Lithuania ties. Following 20th-century upheavals, both joined the EU and NATO, cementing collaboration on economic, security, and cultural fronts. In 2024, Poland and Lithuania sought EU and NATO assistance to bolster their shared border defense, emphasizing the importance of safeguarding the eastern flank of the EU and NATO. This joint initiative underscores their commitment to regional security and mutual support (euronews.com).

12. Brazil and Argentina

Long-time competitors for South American influence, Brazil and Argentina have transformed rivalry into partnership, particularly through founding Mercosur, a regional trade bloc boosting cooperation. Established in 1991, Mercosur includes Argentina, Brazil, Paraguay, and Uruguay, aiming to promote free trade and fluid movement of goods, people, and currency. In December 2024, the European Union and Mercosur concluded negotiations on a Partnership Agreement, marking a significant milestone in their economic integration. (gov.br) This agreement is expected to enhance trade relations and attract investment, further solidifying the economic ties between Brazil and Argentina (gov.br).

13. Italy and Austria

From Habsburg dominance to bitter World War I foes, Italy and Austria have overcome deep-seated animosities. Their European partnership today is strengthened by shared tourism interests and regional EU collaboration. Italy remains Austria’s second-largest trading partner, with trade relations particularly close with the Northern Italian regions. The majority of the approximately 300 subsidiaries of Austrian companies in Italy are located in the north of the country. For Austrian holidaymakers, Italy is still the unrivalled number one holiday destination, which is reflected in about 1.9 million visits per year (bmeia.gv.at). Both countries are full members of the Council of Europe, European Union, Organisation for Economic Co-operation and Development, and Organization for Security and Co-operation in Europe. The Tyrol-South Tyrol-Trentino Euroregion, established in 1998, further exemplifies their collaborative efforts.

14. Serbia and Montenegro

Following the dissolution of Yugoslavia, Serbia and Montenegro maintained a political union until 2006. After Montenegro’s independence, both nations have pursued European Union integration and fostered cross-border cooperation. In 2023, they signed a €7.1 million cross-border partnership under the EU’s IPA III financial framework, focusing on employment, social rights, health, tourism, and cultural heritage. This initiative aims to enhance regional collaboration and support the EU integration process for both countries (connectingregion.com).

15. United Kingdom and Ireland

Centuries of conflict ended with the Good Friday Agreement, signed on 10 April 1998, signaling the start of a cooperative era. The UK and Ireland now coordinate on trade, security, and cultural exchange. In 2023, they marked the 25th anniversary of the Agreement, reflecting on its transformative impact on Northern Ireland’s peace and prosperity. Despite occasional post-Brexit tensions, both nations remain committed to upholding the Agreement’s principles and fostering a positive future for all citizens (gov.uk).

Conclusion

Overcoming historical rivalries is challenging but achievable. The examples of France and Germany, the United States and Japan, and others demonstrate that reconciliation can lead to enduring peace, economic growth, and regional stability. Such transformations not only benefit the nations involved but also contribute to global harmony. These instances offer hope for future reconciliations, highlighting the potential for former adversaries to build cooperative and prosperous relationships.