Nikodim Rotov

Nikodim was born in Frolovo in south-west Russia. Ordained in 1960 at the age of 31, the youngest bishop in the Christian world at the time, he went on to become one of the six presidents of the World Council of Churches.
According to the Mitrokhin Archive, which claimed deep Communist penetration of the Russian Orthodox Church, Nikodim was a KGB agent whose ecumenical activity with the Roman Catholic Church and the WCC served to further Soviet goals. The KGB assigned Nikodim the codename "Svyatoslav". Nikodim is said to have participated in negotiating a secret 1960s agreement between Soviet and Vatican officials that authorized Eastern Orthodox participation in the Second Vatican Council in exchange for non-condemnation of atheistic communism during the conciliar assemblies.
Nikodim collapsed and died in 1978 while in Rome for the installation of Pope John Paul I. The new pope, who himself died a few weeks later, prayed over him in his final moments. Provided by Wikipedia