[1] Spyridon Abou Rjaileh was born in Karssoun, Mount Lebanon in 1885, after which his family moved to Ashrafieh in East Beirut.
He then attended the Ecole des Trois Docteurs in Beirut, followed by studies at the Kasibiya school in Damascus, Syria.
In 1914, Theodosius was appointed a liaison officer between the Antiochian patriarchate and the Turkish government serving the Orthodox Christian communities in Syria and Lebanon.
Theodosius was elected Metropolitan Archbishop of Tyre and Sidon in south Lebanon, a position he held for 25 years.
Theodosius guided the election of a new archbishop for the Syrian Orthodox in North America that resulted in the consecration of Antony Bashir.