Grigorios Pleiathos. Born as Petros Pleiathos in Triantaro, Tinos, in 1890. He studied Theology at the Theological School of Athens. On August 23, 1916, he was tonsured a monk. He was ordained Deacon on September 1, 1916, by Metropolitan Athanasios of Syros, and Priest on April 14, 1919. On April 21, 1919, he received the rank of Archimandrite. He served as a Preacher in the Metropolis of Kalavryta (1916–1919) and in the Metropolis of Syros (1919–1920). In 1920 he was released from the Preacher position but remained close to Metropolitan Athanasios of Syros. In November 1922, he returned to the Preacher position. On December 21, 1922, at the Holy Church of Saint Irene in Athens, he was ordained Metropolitan of Chalkida. The ordination was performed by Metropolitan Athanasios of Syros, assisted by Metropolitans Germanos of Dimitriada and Alexandros of Anion (Ecumenical Patriarchate). On September 29, 1968, he retired from active service by Legislative Act LΣΤ΄/1968. He passed away in Chalkida on July 23, 1971.