Covilhã's arrival in Ethiopia also marked the beginning of Portuguese-Ethiopian relations which culminated in the formal invitation for the Portuguese to interfere directly in the affairs of Abyssinia in the Ethiopian–Adal war of 1541. The sustained Portuguese presence in Ethiopia also led to the influx of Jesuit missionaries into the country although their success at converting the population to Catholicism was mixed. From their base in the city of Fremona, the Jesuits were able to convert the Ethiopian Emperors Za Dengel and Susenyos I to the faith in the 17th century but this resulted in a series of devastating rebellions and revolts against Catholic rule. Following the abdication of Susenyos I in favor of his son Fasilides in 1631, the Jesuits were expelled from the country resulting in several centuries of little to no contact between Ethiopia and Europe.