On 26 April 1994, the Republic of Lithuania and Poland signed an agreement on friendly relations and good neighboring cooperation, laying down a foundation for the strategic partnership between the two countries. Lithuania's accession to NATO on 29 March 2004Lithuania in North Atlantic Treaty Organisation, 2004–2006, Vilnius, 2006. was an important factor that consolidated the country's independence; the foundations for the accession were laid in Washington on 1 February 1998, when the US, Lithuania, Latvia, and Estonia signed a Partnership Charter. The Charter endorsed a common goal of working together to create conditions for the integration of the so-called Vilnius Group into European and trans-Atlantic political, economic, and security structures, including NATO.
