The Church of the Assumption behind the port is one of the main attractions of Syros. There, is situated the authentic image of the Assumption of Domenikos Theotokopoulos (El Greco), which collects naturally the interest of the visitors. This icon is in the church since the 19th century, but only in 1983 it was revealed that it is authentic, youthful work (1562-1564) of the great painter.
The Assumption was built in 1828-1829 and is the second oldest church inafter the Cathedral, the of the Savior (1824). It is tri-aisled basilica and externally had open arches, which have now been closed with iron covered by glass windows. The cells had been built in the northern and eastern side of the enclosure. Inscription on the south side of the entrance reports the chronology of the building (1829) and renovation (1847-50).
The Assumption in the interior has a distinctive architecture and decoration. The columns are painted so like to marble, domes and vaults of wood. The wooden frame of the dome, is viewed from the place set apart for women, looks like an upturned ship’s hull
During the Second World War, on 23th of October 1943, a bomb destroyed the sanctuary of the Assumption in time of liturgy.
Some icons of the Assumption are devoted by unions and guilds, such as the icon of the Forty Martyrs of D. Kostarakis dedicated from the porters of the shipyard in 1863 and the image of St. Anthony, the work of M. Michalovits priest from the guild of bourgouzidon (drilling) of 1872.