Career
He is known for his leadership of Martaban"s musket and artillery corps at the battle of Martaban (1540-1541) against Toungoo Burma. Though Seixas" land and naval troops, primarily made up of Portuguese and other foreign mercenaries, kept the besiegers at bay for seven months, Toungoo forces eventually broke through and the city was sacked. He had brought with him two valuable bracelets, which he said were awarded to him by Saw Binnya in recognition of his faithful service.
He sold the bracelets for 36,000 ducats.
The dealers, according to Pinto, resold the bracelets to the ruler of Narsinga for 80,000 ducats.
