The chief general cause was the weakness and mutual enmity of the rulers with whom he came in contact. He had not to strive with the great Mughals; he did not come directly in contact with Ismáil Sháh, who favoured instead of opposing him; nor did he have cause to attack the powerful Emperor of China. The Hindu Zamorin of Calicut, the Muhammadan Nawáb of Diu, the half savage Sultan of Malacca, the Arab King of Ormuz, were none of them great and powerful monarchs. All had external as well as internal enemies, and Albuquerque was quick to perceive and make use of this circumstance. The only great ruler he came into opposition with was Yusaf Adil Sháh of Bijápur, who, fortunately for the Portuguese, died in 1510. The division of India into hostile kingdoms was especially favourable to the progress of the Portuguese. Albuquerque was able to play off Hindu Rájás against Muhammadan kings: nor were monarchs even of the same faith necessarily united in bonds of friendship. Thus the Rájá of Cochin was the declared enemy of the Zamorin of Calicut, and the Muhammadan kings of the Deccan were too busy in fighting over the disruption of the great Báhmani kingdom to make a general effort against the new-comers. The existence of local jealousies and rivalries enabled Albuquerque, like later European rulers of India, to make good the position of his countrymen.
The special causes of the success of the Portuguese are to be found in the superiority of their ships, their artillery, and their soldiers. The Portuguese ships at the beginning of the sixteenth century, though much smaller than the great galleons which they afterwards built for the Indian trade, were much more efficient than the Arab vessels. They had to be both well built and well fitted to accomplish the long and perilous voyage round the Cape of Good Hope, whereas the Arab ships were only intended to sail across the Indian Ocean with the favourable monsoon and then up the quiet waters of the Red Sea or Persian Gulf. But the Portuguese did not depend on sailing vessels alone in their maritime battles; they built galleys in imitation of the native craft, and secured good sailors for them by offering increased pay.
The excellence of the Portuguese artillery and the skill of the gunners was another main cause of their victories. The natives, indeed, understood the use of powder and of cannon; as many as 300 pieces of ordnance were captured at Malacca; but the Portuguese guns were always better served than those of their opponents. It was noticed at the siege of Benastarim that one of Rasúl Khán's guns did more damage than the rest, and it was soon discovered that it was being served by a Portuguese renegade. The arquebuses or clumsy muskets of the Portuguese also did them good service, though they cannot be compared to the more efficient arms of precision which came into use in the next century. Bows and arrows were the chief weapons on both sides, and the superiority of the Portuguese crossbowmen is constantly described in different engagements.
But neither ships nor arms would have effected much without brave hearts. And the Portuguese, in this their heroic period, gave evidence of a tried and adventurous courage which has seldom been equalled. Albuquerque's most serious repulse, at Aden, was due not to the reluctance but to the over impetuosity of his men. Again and again proofs of conspicuous gallantry were given, and many anecdotes might be quoted which testify to the bravery of both officers and men. But the discipline of the Portuguese was not equal to their courage. The soldiers and sailors were always ready to follow their officers, but the officers were apt to have ideas of their own with regard to the duty of obedience. The insubordination of Albuquerque's captains during his first expedition against Ormuz was imitated on many other occasions. Even the most severe examples failed to establish perfect discipline, and it was by no means the worst of the captains who were the most disobedient. But in spite of this defect the soldiers and the officers of Albuquerque were worthy of their leader. They had inherited their warlike disposition from their fathers; they had been trained to courage and endurance through centuries of fighting with the Moors both in the Peninsula and in Morocco; and their hideous cruelty to their conquered foes was as much a part of their nature as it was typical of the century in which they lived.
Albuquerque's own character counted for much in his success. He was comparatively an old man when he took up his governorship, and his scheme of policy was by that time carefully matured. To that policy he adhered unflinchingly from the beginning to the end of his career. His extraordinary tenacity of purpose was one of his most remarkable characteristics. He swore at the time of his first repulse at Ormuz that he would return, and he did. He insisted on the capture and retention of Goa, in spite of many varieties of opposition, and he gained his point. There can be little doubt that had he survived he would have succeeded in his cherished ambition of conquering Aden and closing the Red Sea to the commerce of the East.
With this tenacity of purpose went a wide and remarkable tolerance. The favourable countenance he showed to the Hindus was due to his nature as well as to his scheme of policy. With regard even to the Muhammadans, whom he hated, he could show a certain tolerance which would not have been found in a crusader. He sent embassies to Sháh Ismáil, and the Kings of Gujarát and Bijápur, and was ready to bear with the Moslems in Malacca and in India, until he grasped the irreconcilable nature of their enmity to the Portuguese. He possessed an intuitive knowledge of the best way to deal with Asiatic peoples. He understood the importance of pomp and ceremony, and the influence exerted by the possession of the prestige of victory.
Throughout there was something of the grandiose in his nature and his views. His project of establishing an empire in India naturally seemed absurd to his contemporaries. And the attempt to realise it exhausted the Portuguese nation. But the existence of the English empire in India has shown that Albuquerque's idea was not impracticable in itself; it was his nation which proved inadequate to the task. Albuquerque's courage and his cruelty, his piety and his cunning, were not peculiar to himself; they were shared by other men of his time and country. But his tenacity of purpose, his broadminded tolerance, and his statesmanlike views were absolutely unique, and helped to win for him his proud designation of Affonso de Albuquerque the Great.