 Moreover, hundreds of churches were destroyed during the invasion, and an estimated 80% of the manuscripts in the country were destroyed in the process.Adal's use of firearms, still only rarely used in Ethiopia, allowed the conquest of well over half of Ethiopia, reaching as far north as Tigray.The complete conquest of Ethiopia was averted by the timely arrival of a Portuguese expedition led by Cristovão da Gama, son of the famed navigator Vasco da Gama.