Salahuddin's father sultan Ali had been engaged in a mortal combat against the Portuguese in Melaka, but hostilities had paused temporarily after his death.

However, in September 1537, an Acehnese fleet appears before Melaka, carrying a standing regiment of circa three thousand men.

The Acehnese land successfully but cannot invest the fortress.

After some ferocious fighting, they have to withdraw with great losses after two days.

Since the expedition is not mentioned in the local chronicles we cannot be sure that Salahuddin was still the ruler at this time.

From the account of Fernão Mendes Pinto it appears that his brother "Alaradim" (Alauddin) was already on the throne by 1539.

The much later chronicle Bustanus Salatin will alleges in about 1640 that Salahuddin lived for nine years after his deposition until his death in 1548.

It is thus somewhat unclear whether he was deposed before or after the launch of an unsuccessful attack on Melaka.

Hoesein Djajadiningrat believed that the coup came first and the attack was led by Alauddin al-Kahar, while Denys Lombard places the coup two years after the attack, which he believes was led by Salahuddin himself.