Pérez de Cuéllar joined the Ministry of Foreign Affairs in 1940 and the diplomatic service in 1944, serving subsequently as Secretary at Peru's embassies in France, where he met and married his first wife (the former Yvette Roberts); the United Kingdom; Bolivia; and Brazil. Later, he was ambassador to Switzerland, the Soviet Union (at the same time in Poland), and Venezuela. From his first marriage, Perez de Cuellar had a son (Francisco, born in Paris) and a daughter (Agueda Cristina, born in London).