The latter, as a Christian empire, and the seat of that mythical monarch, Prester John, was a subject of great interest to the Christians of Europe. It has been said that John II of Portugal sent one of his equerries João Peres de Covilhão to Abyssinia, where he had become a person of influence and eventually {128} died. Ambassadors had also been sent to that country by way of Melinda in Vasco da Gama's second voyage to the East, and had been favourably received by David, the then Emperor of Abyssinia. The existence Of such a Christian empire interested most Europeans only on account of its religion, but Albuquerque looked on it from a political aspect. He hoped to make use of the Abyssinians to attack Egypt from the South and overthrow the Muhammadan dynasty reigning there. In case this could not be accomplished, he formed a scheme by which the waters of the Nile should be diverted, so as to run through Abyssinia to the Red Sea, and thus destroy the fertility of Egypt. He even went so far in pursuance of his idea as to request the King of Portugal to send him experienced miners from the island of Madeira, who were accustomed to dig through rocks. Another plan he formed was to send a detachment to Medina to carry off the body of Muhammad. But he felt his present voyage to be rather one of exploration, and so, after sailing about throughout the summer of 1513, he left the Red Sea in the month of August for India. This cruise was one of great importance to the Portuguese, and a knowledge of the coasts, and of the navigation of the Red Sea was obtained, which proved in after years to be very useful. Before departing Albuquerque burnt many of the ships which were moored in the harbour of Aden, and he promised to return speedily and conquer the city.