This knowledge, once acquired, was promptly applied to the work of navigation. Madeira was discovered in 1418; the Canaries in 1427; the Azores in 1432. The first and last were colonised and rapidly became populous. To the West the explorers pushed no farther for the present, but to the south they reached Cape Blanco in 1441, Senegambia and Cape Verde in 1445, and the Cape Verde Islands in 1460. In 1469, they turned into the Gulf of Guinea, and in 1471 were the first Europeans to cross the Equator. Their search, at first random, now became definite. They believed it was only necessary to keep on and they would round the southern extremity of Africa and reach Abyssinia and India by sea, a hope which became a certainty in 1487, when Bartholomew Diaz finally reached the Cape of Good Hope. Meanwhile, a political revolution had been going on. The strong kings of the line of Aviz had won for the Crown a moral preponderance over the nobility and clergy. The latter resisted the royal encroachments, but the municipalities joined the monarchs in the struggle against them. The king who established centralised despotism--the Richelieu of Portugal--was John II., the third of the Aviz dynasty, and who reigned from 1481 to 1495. Under his rule, the whole military power was concentrated in the Crown; the nobility became a class living at Court; the king was the fountain of all honour and advancement; local officers were replaced by officials appointed by and responsible to the central government; piece by piece the independent functions of the municipalities were taken away. Concentration of power in the hands of monarch and bureaucracy produced its inevitable effect. A short period of marvellous brilliancy in arms, statecraft, literature, and the arts was followed by sudden decay. The self-governing municipalities had nurtured a multitude of men whom small power and responsibility fitted for great things. The nation turned eagerly to the work of exploration and conquest and prosecuted it efficiently.