Complex sentence: The Ottomans taught the Acehnese how to found their own cannons, some of which reached considerable size, and the craft of making cannons had spread throughout the Maritime Southeast Asia; famous cannons were made in Makassar, Mataram, Java, Minangkabau, Melaka and Brunei.
Split into simpler sentences: The Ottomans taught the Acehnese how to forge their own cannon, some of which reached considerable size; the craft of making such weapons had spread throughout the Maritime Southeast Asia. Famous cannons were made in Makassar, Mataram, Java, Minangkabau, Melaka and Brunei.