period. However, the church was again damaged by the invasion of the Persians in 1795. The cathedral's interior took on a different look between 1850 and 1860, when the Russian artist and general Knyaz Grigory Gagarin (1810–1893) composed an interesting series of the murals, though a number of medieval frescoes were lost in the process. A portion of the murals on the western wall were executed by the Georgian artist Levan Tsutskiridze in the 1980s. The stone iconostasis dates to the 1850s, and was also created according G. Gagarin's design. It replaced the wooden iconostasis burned during the Persian invasion in 1795. To the left of the altar is the venerated Grapevine cross which, according to tradition, was forged by Saint Nino, a Cappadocian woman who preached Christianity in the Caucasus in the early 4th century. King Vakhtang III gave the reliquary itself in the early 14th century. The Sioni Cathedral was where the Russian Imperial manifesto on the annexation of Georgia was first published. On April 12, 1802, the Russian commander-in-chief in Georgia, General Karl von Knorring, assembled the Georgian nobles in the cathedral, which was then surrounded by Russian troops. The nobles were forced to take an oath to the Russian Imperial crown; any who disagreed were taken into custody. Sioni Cathedral remained functional through Soviet times, and was partially renovated between 1980 and 1983. Architecture The Sioni Cathedral is a typical example of medieval Georgian church architecture of an inscribed cross-in-square design with projecting polygonal apses in the east façade. Main entrance is in the west side. The dome with the tholobate is supported by the altar wall and two freely standing pillars (a more advanced design that appeared after the 11th century). Transition from the pillars to the tholobate is via pointed arches. In addition, the pillars are connected to the northern and southern walls by helm-shaped arches (probably 16th century). The yellow tuff from which the cathedral was built comes from Bolnisi, a town southwest of Tbilisi. The facades are simple, with few decorations, although there are bas-relief carvings of a cross and a chained lion on the western side and an angel and saints on the north. All sixteen windows have carved ornamental frames. Shallow carvings indicate late decoration. Bell towers North of the cathedral, within the courtyard, is a freestanding three-story bell tower dating from the 1425 reconstruction by King Alexander I. Largely