generate questions: The Swahili built Mombasa into a major port city and established trade links with other nearby city-states, as well as commercial centres in Persia, Arabia, and even India. By the 15th-century, Portuguese voyager Duarte Barbosa claimed that "Mombasa is a place of great traffic and has a good harbour in which there are always moored small craft of many kinds and also great ships, both of which are bound from Sofala and others which come from Cambay and Melinde and others which sail to the island of Zanzibar."
Who build the major port city in Kenya? {sep_token} What is the name of the port city that was created? {sep_token} What voyager said that Mombasa was a great harbour and moored small crafts and great ships? {sep_token}