The trade with English and Danish had enabled Banten to buy arms and developed troops of trained musketeers, improving city fortifications and buying cannons. In 1644 the ambassador of Mataram arrived and proposed an alliance, which was declined by Banten that now set their eyes on Cirebon. At that time Cirebon was a vassal state as well as the westernmost province of Mataram. Historically Banten and Cirebon are linked through their common ancestral founding father Sunan Gunung Jati, and Banten saw the currently weakened Cirebon as rightfully belongs within Banten's sphere of influence.