Complex sentence: In the 16th century, the Brunei empire's influence also extended to Kapuas river delta in West Kalimantan, as the Malay Sultans of Sambas and Pontianak, as far as the Sultans of Samarinda and Banjarmasin, treated the Sultan of Brunei as their leader.
Split into simpler sentences: In the 16th century, the Brunei empire's influence also extended as far as Kapuas river delta in West Kalimantan. Other Malay sultans of Pontianak, Samarinda as far as Banjarmasin, treated the Sultan of Brunei as their leader.