Patriarch Joachim III (born Christos Demetriades or Devetzis) was Ecumenical Patriarch during the years 1878-1884 and 1901-1912.
In 1852 he was ordained deacon, taking the name Joachim, by Metropolitan Nikandros of Pogonianis in Bucharest, where he remained until 1854, studying and learning the Romanian language. From 1854 to 1860 he served as a priest-deacon in the Greek churches of Vienna, continuing his studies and learning German.
Spiritual child of Metropolitan Kizikos and later Ecumenical Patriarch Joachim II, after the latter’s election to the Ecumenical throne he was ordained an elder in 1863 and appointed Grand Protosyngelos. On 10 December 1864 he was elected Bishop of Varna, a position he held until 1874. After the return of Joachim II to the ecumenical throne, Joachim assumed the Holy Metropolis of Thessaloniki on 9 January 1874, which he held until 1878.
On 4 October 1878, after the death of Joachim II, he was elected Ecumenical Patriarch. During his Patriarchate he successfully regulated many administrative matters and took special care to strengthen education. He built the Joachimos Parthenagogue and in 1880 he reopened the patriarchal printing press and published the magazine Ecclesiastical Truth. He also founded the Patriarchal Library, laid the foundations of the new building of the Great School of the Nation on the hill of Fanari (30 January 1880) and expanded the buildings of the Patriarchate.
In 1879 he recognized the autocephaly of the Serbian Church and transferred the Diocese of Drystra to the Church of Romania. In 1882 he ceded the Metropolises of Thessaly and Arta to the Church of Greece, after their political incorporation had already taken place.
On 30 March 1884 he was forced to resign because he reacted to the demands of the Turkish government to abolish the privileges granted to the Orthodox Church[16]. During the negotiations with the Ottoman government he had submitted his resignation three times in December 1883, which were not accepted.
On 25 May 1901 he returned to the ecumenical throne, as he was elected Ecumenical Patriarch for the second time, succeeding the deposed Constantine V. During his 2nd patriarchate he completed and improved the finances of the Patriarchate, founded an orphanage for girls on the island of Proti and for boys in Prigipo, and established the School of Languages and Commerce with students and Turks, He completed the construction of the Valouklis Hospitals, assisted mainly by the families of Zarifis, Mavrogordatos, Vallianos, Negreponis, Koronios, Siniosoglou and others from Greece, Bulgaria, Romania, Russia as well as from Egypt.
He was awarded the highest decorations of the Ottoman Empire, Austria-Hungary and the Kingdoms of Greece, Bulgaria, Egypt, Russia and Romania. On 21 March 1912 the University of Athens honoured his contribution by awarding him an honorary doctorate in theology. Joachim III patriarched until 13 November 1912, when, after a few days of illness, he died (26 November) and was buried in the patriarchal cemetery of the Zoodochos Fountain of Valouklis in Constantinople, shortly after the Greek troops entered Thessaloniki.