Cosmas Indicopleustes (; also known as Cosmas the Monk) was a Greek merchant and later hermit from Alexandria of Egypt. He was a 6th-century traveller who made several voyages to India during the reign of emperor Justinian. His work Christian Topography contained some of the earliest and most famous world maps. Cosmas was a pupil of the East Syriac Patriarch Aba I and was himself a follower of the Church of the East. Voyage Around AD 550, while a monk in the retirement of a Sinai cloister, Cosmas wrote the once-copiously illustrated Christian Topography, a work partly based on his personal experiences as a merchant on the Red Sea and Indian Ocean in the early 6th century. His description of India and Ceylon during the 6th century is invaluable to historians. Cosmas seems to have personally visited the Kingdom of Axum in modern day northern Ethiopia, as well as Eritrea. He sailed along the coast of Socotra, but it cannot be ascertained that he really visited India and Ceylon. Indicopleustes "Indicopleustes" means "Indian voyager", from "(I) sail". While it is known from classical literature, especially the Periplus Maris Erythraei, that there had been trade between the Roman Empire and India from the first century BC onwards, Cosmas's report is one of the few from individuals who had actually made the journey. He described and sketched some of what he saw in his Topography. Some of these have been copied into the existing manuscripts, the oldest dating to the 9th century. In 522 AD, he mentions several ports of trade on the Malabar Coast (South India). He is the first traveller to mention Soriyani Christians in present-day Kerala in India. He wrote, "In the Island of Taprobane (Ceylon), there is a church of the Christians, and clerks and faithful. Likewise at Malé where the pepper grows; and in the town of Kalliana, there is also a bishop consecrated in Persia." Christian Topography A major feature of his Christian Topography is his worldview that the world is flat and that the heavens form the shape of a box with a curved lid. He was scornful of Ptolemy and others who held that the world was spherical. Cosmas aimed to prove that pre-Christian geographers had been wrong in asserting that the earth was spherical and that it was in fact modelled on the tabernacle, the house of worship described to Moses by God