Between 1528 and 1540 armies of Muslims, under the Imam Ahmad Ibn Ibrihim Al -Ghazi, entered Ethiopia from the low country to the southeast, and overran the kingdom, obliging the emperor to take refuge in the mountain fastnesses. In this extremity recourse was again had to the Portuguese. John Bermudez, a subordinate member of the mission of 1520, who had remained in the country after the departure of the embassy, was, according to his own statement (which is untrustworthy), ordained successor to the Abuna (archbishop), and sent to Lisbon. Bermudez certainly came to Europe, but with what credentials is not known.

In response to Bermudez’s message, a Portuguese fleet under the command of Estêvão Da Gama, was sent from India and arrived at Massawa in February 1541. Here he received an ambassador from the Emperor beseeching him to send help against the Muslims, and in the July following a force of 400 musketeers, under the command of Cristóvão Da Gama, younger brother of the admiral, marched into the interior, and being joined by native troops were at first successful against the enemy; but they were subsequently defeated at the Battle of Wofla (28 August 1542), and their commander captured and executed. On February 21, 1543, however, Ahmad was shot and killed in the Battle of Weyna Daga and his forces totally routed. After this, quarrels arose between the Emperor and Bermudez, who had returned to Ethiopia with Gama and now urged the emperor to publicly profess his obedience to Rome. The Emperor refused to do, and at length Bermudez was obliged to make his way out of the country.