SANDOMIR, or SEDOMIENZ, a town of Russian Poland, in the province of Radom, is one of the oldest towns of Poland, being mentioned in annals as early as 1079 ; from 1139 to 1332 it was the chief town of the principality. Under Casimir IIL it received extensive privileges and reached a high degree of prosperity and strength. In 1429 it was the seat of a congress for the establishment of peace with Lithuania, and in 1570 the well-known "Consensus Sandomiriensis" was held there for uniting the Lutherans, Calvinists, and Moravian Brethren. Subsequent wars, and especially the Swedish, ruined the town still more than numerous conflagrations, and in the second part of the 18th century it had only 2060 inhabitants. It is now a quite unimportant place, but retains a few remarkable monuments of its past. The beautiful cathedral, rising on a high hill above the Vistula, and facing the plains of Galicia, was built between 1120 and 1191 ; it was rebuilt in stone in 1360, and is thus one of the oldest monuments of old Polish architecture. The churches of St Paul and St James are fine relics of the 13th century. In 1881 the population was 6265, or, including the suburbs, 14,710.