Why did Portugal send musketeers to assist Emperor Galawdewos in 1541?

In 1541, the Portuguese sent 400 musketeers to assist Emperor Galawdewos primarily because their own strategic and economic interests in the Red Sea were being imperiled by the rising power of Muslim forces under Ahmad ibn Ibrahim al-Ghazi.21

By providing these troops to train the Ethiopian army in European military tactics, the Portuguese sought to counter the expansion of the Adal sultanate, which had been conducting a jihad against the Christian Ethiopian state. This intervention proved decisive; with the support of the musketeers, Galawdewos was able to employ a successful hit-and-run strategy that led to the defeat and death of Ahmad in 1543, effectively securing north-central Ethiopia for the Christians.21