But Swahili civilization didn't begin its rapid development until the 8th century, when Arab traders arrived seeking goods that they could trade on the vast Indian Ocean network, the Silk Road of the Sea. And of course those merchants brought Islam with them, which, just like in West Africa, was adopted by the elites, who wanted religious as well as commercial connections to the rest of the Mediterranean world. In many of the Swahili states, these Muslim communities started out quite small, but at their height, between the 13th and 16th century, most of the cities boasted large mosques. The one in Kilwa even impressed Ibn Battuta, who of course visited the city because he was having the best life ever. Most of the goods exported were raw materials like ivory and animal hides and timber. It's worth noting, by the way, that when you're moving trees around, you have a level of sophistication to your trade that goes way beyond the Silk Road. I mean, if you'll recall, they were just trading like tortoise shells and stuff.