The armies then marched down to Ayutthaya. There, they were kept at bay for weeks by the Siamese fort, aided by three Portuguese warships and artillery batteries at the harbor. The invaders finally captured the Portuguese ships and batteries on 7 February 1564, after which the fort promptly fell. The Siamese king surrendered on 18 February 1564. Bayinnaung took all four white elephants, among other loot, and sent the fallen king to Pegu. He appointed Mahinthrathirat, a son of the fallen king, vassal king of Siam, and left a garrison of 3000. Thai sources state that Bayinnaung also took Prince Ramesuan (ราเมศวร), the eldest son of Maha Chakkraphat, back with him as well as Phraya Chakkri (พระยาจักรี), the chancellor of Ayutthaya, and Phra Sunthon Songkhram (พระสุนทรสงคราม), the military chief of Ayutthaya.