The Portuguese authorities were concerned that Aceh allowed trade with the
Dutch East India Company and wished to erect a fortress at the strategically vital estuary of the
Aceh River. a fleet was launched under the Viceroy
Martim Afonso de Castro reaching there in June 1606. After negotiations with the sultan had failed the invaders attacked. Perkasa Alam asked the sultan to lead the army, his request was granted; In the following
battle, the Portuguese attack was halted. De Castro probably heard of a strong Dutch and
Johorese force that had attacked
Melaka and therefore canceled the invasion. Due to his military feat Perkasa Alam came in high esteem at the court. His mother Puteri Raja Inderabangsa, the sultan's sister, prepared the way for his rise by distributing money to the mercantile elite, the
orang kayas. When Sultan Ali suddenly died on 4 April 1607, Perkasa Alam secured the loyalty of the palace guards by generous gifts, gave the officers attractive promises, and threatened the
qadi who opposed his enthronement. On the same day as his uncle died he was, therefore, able to ascend the throne, taking the name Iskandar Muda. Under him Aceh would reach its political apogee. ==References==