The Panteleimon Monastery
The Panteleimon Monastery, also called Rossikon, is a Rus' establishment on Mount Athos. The present large complex of the Rossikon, situated north of Daphne on the southwest shore of the Athonite peninsula, is of modern construction. Rossikon had its origins in two Byzantine monasteries, the Theotokos of Xylourgou and St. Panteleemon, also called "of the Thessalonican," which merged in the 12th century.
The Xylourgou monastery (present-day Skete of Bogoridica or Theotokos) was located in the northwest part of the peninsula and inhabited in the 10th century by monks from Rus. The monastery of St. Panteleimon (present-day Palaiomonastero), located half-way between modern Rossikon and Kartes, was founded in the late 10th century, probably by Leontios of Thessalonike. It owned a dock and tower (pyrgos) at the site of modern Rossikon. St. Panteleimon fell into decline in the 12th century and was virtually deserted by 1169, when it was occupied by the Rus monks of Xylourgou. The proton of Athos gave St. Panteleimon to the Rus on condition that they restore and fortify the complex. The Rus hegoumenos assumed the leadership of both St. Panteleimon and of Xylourgou, which was designated an annex (paramonasterion). The reorganized monastery took the name of “the monastery of the Rus” honored with the name of St. Panteleimon. Panteleimon prospered, especially during the period of Serbian domination over Athos, receiving substantial estates from Serbian princes. Many of these properties were lost, however, after the Turkish conquest of Macedonia in the 15th century.
The archives contain 20 Byzantine acts (dating between 1030 and 1430), 15 Serbian documents (1349-1429), as well as later Russian and Moldavian acts. Panteleimon also owned lands on Lemnos. Approximately 169 Greek manuscripts of Byzantine date are preserved in the library, most notably cod. 6, a richly illustrated copy of the homilies of Gregory of Nazianzus. The church formerly possessed a steatite Panagiarion inscribed with the name of Alexios III of Trebizond.
Oxford Dictionary of Byzantium