The first true maritime trade network in the Indian Ocean was by the Austronesian peoples of Island Southeast Asia, who built the first ocean-going ships. They established trade routes with Southern India and Sri Lanka as early as 1500 BC, ushering an exchange of material culture (like catamarans, outrigger boats, lashed-lug and sewn-plank boats, and paan) and cultigens (like coconuts, sandalwood, bananas, and sugarcane); as well as connecting the material cultures of India and China. Indonesians, in particular were trading in spices (mainly cinnamon and cassia) with East Africa using catamaran and outrigger boats and sailing with the help of the Westerlies in the Indian Ocean. This trade network expanded to reach as far as Africa and the Arabian Peninsula, resulting in the Austronesian colonization of Madagascar by the first half of the first millennium AD. It continued up to historic times.