In preparation, Fr. Anastasios turned to postgraduate studies in history of religion including ethnology, science of religions, missiology and African studies. In this pursuit, he studied at universities in Hamburg and Marburg, with research work at the Makerere University in Uganda to collect material for his doctoral thesis "The Spirit Mbandwa and the Framework of Their Cults: A Research of Aspects of African Religion".
In 1868, the efforts of Fr. Anastasios and his Porefthentes staff bore fruit in the Bureau of External Missions within the [[Apostoliki Diakonia]] of the [[Church of Greece]], the official publishing house and missionary arm of the Church of Greece that was active in many fields, including Orthodox mission. In 1972, he was [[consecration of a bishop|consecrated]] the [[Titular bishop|titular Bishop]] of Androussa in his position as general director of Apostoliki Diakonia. Also in 1972, Bp. Anastasios was elected by the University of Athens professor of History of Religions having established a center for [[missionary]] studies during 1971 to 1976 at the university.
Furthering his work in missions, Bp. Anastasios, with Fr. Anthony Romeos, founded a [[monastery]] of [[nun]]s, the Convent of St. [[John the Forerunner]], in Kareas, Greece, that would participate in missionary work throughout the world.