The Moluccas are a group of islands west of New Guinea. However, unlike the large modern Indonesian archipelago of the Maluku Islands, to 16th-century Europeans the Moluccas were a small chain of islands, the only place on earth where cloves grew, just west of the large north Malukan island of Halmahera (called Gilolo at the time). Cloves were so prized by Europeans for their medicinal uses that they were worth their weight in gold. 16th- and 17th-century maps and descriptions indicate that the main islands were Ternate, Tidore, Moti, Makian and Bacan, although the last was often ignored even though it was by far the largest island. The principal island was Ternate at the chain's northern end (0°47′N, only in diameter) on whose southwest coast the Portuguese built a stone fort (Forte de São João Baptista de Ternate) during 1522–23, which could only be repaired, not modified, according to the Treaty of Saragossa. This north–south chain occupies two degrees of latitude bisected by the equator at about 127°24′E, with Ternate, Tidore, Moti, and Makian north of the equator and Bacan south of it.