Complex sentence: The earliest known documents written in Swahili are letters written in Kilwa in 1711 A.D. in the Arabic script that were sent to the Portuguese of Mozambique and their local allies.
Split into simpler sentences: The earliest known documents written in Swahili are letters written in Kilwa in 1711 A.D. in the Arabic script. They were sent to the Portuguese of Mozambique and their local allies.