In 2005, Europe celebrated the thirtieth anniversary of the adoption of the Helsinki Final Act that established the Conference on Security and Co-operation in Europe (CSCE). At its 1994 Budapest meeting, the CSCE was transformed into the Organization for Security and Co-operation in Europe (OSCE). The CSCE was the most visible institutional manifestation of the spirit of détente that resulted in closer co-operation between ideological, political and military rivals and a group of non-aligned countries in Europe for the beneﬁt of all of them. Although there had been several setbacks in this co-operation and in the early 1980s it could seem that détente was in retreat, the ascent to power of Mikhail Gorbachev in 1985 contributed to reversing this negative trend and helped to revitalize co-operation across the ideological dividing lines inEurope.Gorbachev’s policywas also to bear some unexpected fruits, the most important – and least expected – of which was the collapse of the Soviet project and the complete redrawing of the political map of Europe. By the end of 1991 Europe was no longer divided into two competing ideological and military blocs. The Soviet empire – both Inner and Outer – was no more, and this fact would have major implications for the development of a new security architecture in Europe.