His Grace, the Very Reverend Theodosios (Sideris) of Ancona was an auxiliary bishop of the Greek Archdiocese of North and South America under the jurisdiction of the Ecumenical Patriarch. He served both the Sixth (Pittsburgh) Archdiocesan and the Ninth (Canadian) Archdiocesan Districts of the Archdiocese before his retirement in 1973.

Vasilios L . Sideris was born on July 20, 1903 in Vryoula, Smyrna, in Asia Minor of the then Ottoman Empire. He attended and graduated from the Rizarios Teacher's College in Athens, Greece. He then entered the Theological School of the University of Athens from which he received a degree in Orthodox Theology in 1935.

While he was attending school, Vasilios entered the Holy Orders in 1926, receiving the name Theodosios, when he was ordained a deacon. As a deacon he was assigned to the Annunciation of the Virgin Mary Greek Orthodox Church in Piraeus for seven years. In 1933, he was ordained a priest and served the Church of St. Alexandros of Palaio Faliro, Athens. For the years of 1936/1937 he served as a teacher and assistant dean at the theological school of Mount Athos.

Father Theodosios arrived in the United States of America on November 3, 1937 and was assigned to serve the Church of Ss. Constantine and Helen in Richmond, Virginia. While in Richmond Fr. Theodosios pursued theological studies at the Union Theological Seminary in Richmond, and from which he received, in 1942, his Master's Degree in Theology. He continued his studies and received his Doctorate in Theology from the Union Seminary in 1947.

In 1954, Fr. Theodosios was assigned as priest at the Church of the Three Hierarchs in Brooklyn, New York. On September 13, 1960, Fr. Theodosios was consecrated Bishop of Ancona by Archbishop Iakovos (Coucouzis) at Holy Trinity Cathedral in New York City.

Following his consecration, Bp. Theodosios served as Auxiliary Bishop to Abp. Iakovos and was assigned to the Sixth Archdiocesan District with his see in Pittsburgh, Pennsylvania. In December, 1967 he was moved to the see in Toronto, Canada to serve as the bishop of the Ninth (Canadian) Archdiocesan District as the first hierarch of the Ninth district.

Bp. Theodosios retired on November 1, 1973 at the age of 70. During his retirement, he has served occasionally at Holy Trinity Greek Orthodox Church in Belleville, Ontario.

Source: http://orthodoxwiki.org/Theodosios_%28Sideris%29_of_Ancona