Sarai (also transcribed as Saraj or Saray, from Persian sarāy, "mansion" or "court") was the name of possibly two cities near the lower Volga, that served successively as the effective capitals of the Golden Horde, a Turco-Mongol kingdom which ruled much of Northwestern Asia and Eastern Europe, in the 13th and 14th centuries. There is considerable disagreement among scholars about the correspondence between specific archaeological sites and the various references to Sarāy, Sarāy-i Bātū ("the Sarai of Batu"), Sarāy-i Barka ("the Sarai of Berke"), Sarāy al-Jadīd ("New Sarai"), and Sarāy al-Maḥrūsah ("Sarai Blessed [by God]") in the historical sources. Old Sarai "Old Sarai" was established by the Mongol ruler Batu Khan (1227-1255), as indicated by both occasional references to the "Sarai of Batu" ("Sarai Batu", Sarāy-i Bātū) and an explicit statement of the Franciscan William of Rubruck, who visited Batu in 1253 or 1254, on his way to the court of the Great Khan Möngke at Qaraqorum. William's statement, "Sarai, the new town that Baatu is making on the Etilia" is considered the first historical reference to the city; a few passages later he refers to the same settlement as "Sarai and the palace of Baatu". The slightly later Persian historian ʿAṭā Malik Juwaynī describes this settlement as both "camp" (muḫayyam) and "city" (šahr), reflecting its dual function, gradual development, and perhaps the lifestyle preferences of its various inhabitants. As the principal seat of Batu, Berke, and their successors, Sarai was effectively the capital of a great empire, although the khan and his court occasionally resided at other sites as well. Various Rus' princes came to Sarai to pledge allegiance to the Khan and receive his patent of authority (yarlyk). In 1261, the city became a seat of the Saray diocese of the Russian Church (Krutitsy), and in 1315 also of a Catholic diocese. It also served, at least occasionally, as the burial site of khans: when he died in 1266, Berke was buried at the "Sarai of Batu", according to the Ilkhanid vizier Rashīd ad-Dīn Faḍlullāh. Berke had presumably continued the development of the city, promoting the settlement of Muslims and attracting Muslim literati, leading later Muslim accounts to credit him with the foundation of the city; this probably led to references to the "Sarai of Berke", although it is doubtful that there was ever an entirely separate city called "Sarai of Berke" (two cities, Sarāy-i Bātū and Sarāy-i