The first Sultan was known as Raden Patah, who was a vassal of Majapahit until 1478.[5] The city was founded as a seaport, next to the now-nonexistent Muria Palaeostrait separating Java from Muria Island (now Mount Muria), although silting has now entirely turned the waterway into land.[6] The Sultanate expanded in the expense of the declining Majapahit and its fragments, conquering the coastal region of Tuban around 1527 and reaching inland areas as far as Malang by 1546.[5] As the capital, the city became an important center for trade and the spread of Islam across the island, and a base of the semi-apocryphal Wali Sanga.