rule over the coastal cities and regions in the form of the new theme of Dalmatia, while leaving the Slavic tribal principalities of the hinterland largely autonomous under their own rulers. The christianization of the Croats and the other Slavic tribes also began at this time. With the weakening of Byzantium, Venice began to see Ragusa as a rival that needed to be brought under its control, but an attempt to conquer the city in 948 failed. The citizens of the city attributed this to Saint Blaise, whom they adopted as their patron saint. The city remained under Byzantine domination until 1204, with the exception of periods of Venetian (1000–1030) and later Norman (1081–1085, 1172, 1189–1190) rule. In 1050, Croatian king Stjepan I (Stephen) made a land grant along the coast that extended the boundaries of Ragusa to Zaton, north of the original city, giving the republic control of the abundant supply of fresh water that emerges from a spring at the head of the Ombla inlet. Stephen's grant also included the harbour of Gruž, which is now the commercial port for Dubrovnik. Thus the original territory of the Ragusan municipality or community comprised the city of Ragusa, Župa dubrovačka, Gruž, Ombla, Zaton, the Elafiti islands (Šipan, Lopud and Koločep) and some smaller islands near the city. The famous 12th century Arab geographer Muhammad al-Idrisi mentioned Ragusa and the surrounding area. In his work, he referred to Ragusa as the southernmost city of Croatia. In 1191, Emperor Isaac II Angelos granted the city's merchants the right to trade freely in Byzantium. Similar privileges were obtained several years earlier from Serbia (1186) and from Bosnia (1189). The Charter of Ban Kulin of Bosnia is also the first official document where the city is referred to as Dubrovnik. Venetian suzerainty (1205–1358) In 1202, the Venetian Republic invaded Dalmatia with the forces of the Fourth Crusade, and Ragusa was forced to pay tribute. Ragusa began supplying Venice with products such as hides, wax, silver, and other metals. Venice used the city as its naval base in the southern Adriatic Sea. Unlike with Zadar, there was not much friction between Ragusa and Venice as the city had not yet begun to compete as an alternative carrier in the trade between East and West; in addition, the city retained most of its independence. The people, however, resented the ever-growing tribute. In the middle of the