Final answer:
The Portuguese attack on Malacca significantly disrupted regional trade by forcing Muslim merchants to divert their routes to avoid Portuguese control, disrupting established trade networks, and leading to a general decline in maritime trade in the area.
Step-by-step explanation:
The effect of the Portuguese attack on Malacca was that it significantly disrupted trade in the region. Before the Portuguese conquest in 1511, Malacca was a thriving trading hub due to its strategic location, which controlled the narrow strait used by trading ships passing between the Indian Ocean and the Pacific. The wealth and prominence of Malacca marked the fifteenth century as a golden age for the region.
However, the Portuguese arrival and subsequent attack turned everything upside down. After Alfonso de Albuquerque's conquest of the city, many Muslim merchants chose to avoid Portuguese Malacca and conducted their trade elsewhere, such as in Johor or the Sultanate of Aceh. This change significantly disrupted the trade patterns and shifted the regional economic balance.
Furthermore, the Portuguese did not just establish a trading post but attempted to gain monopoly control over the lucrative spice trade, adversely affecting the established trade networks. Portuguese aggressive tactics, including looting and sinking the ships of rival traders, especially Muslims, led to a general decline in maritime trade in the affected regions.