Hans-Dietrich Genscher was a German statesman and a member of the liberal Free Democratic Party, who served as the Minister of the Interior of West Germany from 1969 to 1974, and as the Foreign Minister and Vice Chancellor of West Germany and then the reunified Germany from 1974 to 1992, making him the longest-serving occupant of either post. In 1991 he was chairman of the Organization for Security and Co-operation in Europe. A proponent of Realpolitik, Genscher has been called "a master of diplomacy." He is widely regarded as having been a principal "architect of German Reunification." In 1991, he played a pivotal role in the breakup of Yugoslavia by successfully pushing for international recognition of Croatia, Slovenia and other republics declaring independence, in an effort to halt "a trend towards a Greater Serbia." After leaving office, he worked as a lawyer and international consultant. He was President of the German Council on Foreign Relations and was involved with several international organisations, and with former Czech President Václav Havel, he called for a Cold War museum to be built in Berlin.

https://en.wikipedia.org/wiki/Hans-Dietrich_Genscher