His works on national and religious subjects, as well as his portraits (Gomidas, Hovhannes Tumanian, Shirvanzade), earned Yeghishe Tadeosian a place of his own in the Armenian painting of the early twentieth centuries.
Tadeosian (also spelled Tadevosian) was born in Vagharshapat on September 24, 1870. After studies in Tiflis and at the Lazarian School of Moscow, he entered the Moscow School of Painting, Sculpture and Architecture. Painter Vasily Polenov was his teacher and friend. He graduated in 1894 and after a one year stint as a teacher at the Gevorgian Seminary of Holy Echmiadzin, he returned to Moscow in 1896 and began participating in exhibitions by the Peredvizhniki (the Society of Itinerant Artistic Exhibitions) shortly thereafter.
In 1898, he traveled to Palestine with Polenov and would revisit the Middle East several times. In 1901, he moved from Moscow to Tbilisi and became an art teacher. He also participated in local and Russian exhibitions. His early work was influenced by painter Vardges Sureniants but, afterwards, he began to employ impressionistic and pointillistic techniques. In 1916, he became the founder and head of the Union of Armenian Artists in Tbilisi. In 1923, he became one of the founders and first professors of the Academy of Fine Art of Georgia.
Tadeosian earned the title of Emeritus Worker of Art of Soviet Armenia in 1935. He passed away in Tbilisi on January 22, 1936, but he is buried at the Komitas Pantheon, located in the city center of Yerevan. A street in Yerevan and an Art school in Vagharshapat are named after him.