Indian Ocean trade Madagascar at this time leaving behind a lasting cultural and genetic legacy. Chinese fleets under Zheng He criscrossed the Indian Ocean during the early part of the 15th century. The missions were diplomatic rather than commercial, but many exchanges of gift and produces were made. The Portuguese under Vasco da Gama discovered a naval route to the Indian Ocean through the southern tip of Africa in 1497–98. Initially, the Portuguese were mainly active in Calicut, but the northern region of Gujarat was even more important for trade, and an essential intermediary in east-west trade. Venetian interests were directly threatened as
Castles in Portugal Castles in Portugal Castles in Portugal were crucial components of the military throughout its history. The Portuguese learned the art of building fortifications from the Romans and the Moors. The Romans, who ruled and colonized the territory of current-day Portugal for more than four centuries, built forts with high walls and strong towers to defend their populations. The Moors, who invaded the Iberian Peninsula in the year 711 A.D., brought new stonework and heavily fortified gates to the peninsula. Portugal has well-defined geographic boundaries, with the Atlantic Ocean to the south and west, and rivers and mountains to the east