secondly , even if the bitter struggle for the hegemony of the peninsula was punctuated by spells of mutual tolerance , these respites did not last long . the years when the three rival cults were celebrated on an equal footing at Toledo had no more permanent result than had the fleeting Christian-Muslim rapprochement achieved in Sicily under the rule of Frederick 2 , Stupor Mundi , in the same period . in the fifteenth century , at any rate , the average Iberian Christian - like any other European - never referred to the Muslim and the Jewish faiths without adding some injurious epithet . hatred and intolerance , not sympathy and understanding , for alien creeds and races was the general rule . Moors ( i.e Muslims ) , Jews , and gentiles were alike regarded as being doomed to hell fire in the next world . it inevitably followed that they were not likely to be treated with much consideration by Christians in this one . the intolerance was not , of course , only on one side . the Christian crusade had its counterpart in the Muslim jihad , or holy war against the unbeliever . the orthodox Muslim regarded with horror all those who would give associates to God ; and this was just what the Christians did with their trinity , their virgin Mary , and ( to some extent ) with their saints . medieval Europe was a harsh and rugged school , and the softer graces of civilization were not more widely cultivated in Portugal than they were elsewhere . a turbulent and treacherous nobility and gentry ; an ignorant and lax clergy ; doltish , if hard-working , peasants and fishermen ; and a town rabble of artisans and day-labourers , like the Lisbon mob described by E&amp;ccedil;a de Queiroz five centuries later , fanatical , filthy , and ferocious - these constituted the social classes from which the pioneer discoverers and colonizers were drawn . anyone who doubts this need only read the graphic pages of Fern&amp;atilde;o Lopes , the best chronicler of any age or nation , as Robert Southey described him . the first stage of the overseas expansion of Europe can be regarded as beginning with the capture of Ceuta by the Portuguese in 1415 and culminating in the circumnavigation of the globe by the Spanish ship Victoria in 1519-22 . the Portuguese and Spaniards had their precursors in the conquest of the Atlantic Ocean , but the efforts of these adventurers had not changed the course of world history . Vikings had voyaged to north America in the early middle ages , but the last of their isolated settlements on Greenland had succumbed to the rigours of the weather and the attacks of the Eskimo before the end of the fifteenth century . Italian and Catalan galleys from the Mediterranean had boldly ventured into the Atlantic on voyages of discovery in the late thirteenth and early fourteenth centuries ; but what they sought is uncertain , and what they found is equally obscure , though they may well have sighted Madeira and some of the Azores . why did the Iberians succeed where their Mediterranean predecessors had failed ? and why did Portugal take the lead when the Biscayan seamen were as good as any in Europe ? historians are still far from agreed on the precise answers to these questions , but the main impulses behind what is known as the age of discovery evidently came from a mixture of religious , economic , strategic and political factors . these were by no means always mixed in the same proportions ; and motives inspired by Mammon were often inextricably blended with things pertaining to Caesar and to God . at the risk of oversimplification , it may , perhaps , be said that the four main motives that inspired the Portuguese were , in chronological but overlapping order , ( 1 ) crusading zeal , ( 2 ) desire for Guinea gold , ( 3 ) the quest for Prester John , and ( 4 ) the search for spices . an important contributory factor was that , during the whole of the fifteenth century , Portugal was a united kingdom which experienced only one brief episode of civil strife . the consolidation of the power of the Portuguese crown during this period forms a marked contrast with the confused situation obtaining in the rest of Europe . France was distracted by the closing stages of the hundred years war - 1415 was the date of the battle of Agincourt as well as of the capture of Ceuta - and by rivalry with Burgundy ; England by the struggle with France and the wars of the roses ; and Spain and Italy by dynastic and other internal problems . the seizure of Ceuta in 1415 and , more important , its retention , were probably inspired mainly by crusading ardour to deal a blow at the infidel , and by the desire of the half-English princes of Portugal to be dubbed knights on the field of battle in a spectacular manner . economic and strategic motives may also have played a part , since Ceuta was both a thriving commercial centre and a bridgehead for an invasion across the straits of Gibraltar . it has been suggested that the fertile corn-growing regions in the hinterland also formed an attraction for the Portuguese , whose own country was even then normally deficient in cereals . Ceuta was one of the terminal ports for the trans-Sahara gold-trade , though how far the Portuguese knew this before their capture of the city is uncertain . but the occupation of Ceuta undoubtedly enabled them to obtain some information about the negro lands of the upper Niger and Senegal river regions , where the gold came from . they soon began to see that they might , perhaps , establish contact with those lands by sea , and so divert the gold-trade from the caravans of the old Sahara and the Muslim middlemen of Barbary . they had the more incentive to do this since western Europe in general , and Portugal in particular , were then suffering a serious shortage of precious metals . this was partly due to the drain of silver and gold to the east , to pay for spices and other oriental exports , and partly to the insufficient production of the central European mines . the crusading impulse and search for gold were soon reinforced by the quest for Prester John . this mythical potentate was vaguely located in the Indies - an elastic and shifting term that often embraced Ethiopia and east Africa , as well as what little was known of Asia . the passage of time , romantic travellers &apos; tales - of which Marco Polo &apos;s supply the classic example - and wishful thinking , all combined to build up the late medieval belief that Prester John was a mighty , if probably schismatical Christian priest-king . his domains were believed to lie somewhere in the rear of the Islamic powers that occupied a wide belt of territory from Morocco to the Black Sea , thus cutting off Christendom from direct contact with the peoples of Asia and the isolated Coptic Christian kingdom of Abyssinia . from 1402 onwards , occasional Abyssinian monks and envoys reached Europe , and at least one of them got as far as Lisbon in 1452 ; but the Portuguese , like most other people , still seem to have had only a hazy idea of what or where his country was . the mixed motivation behind the Portuguese overseas expansion was explicitly recognized in the papal bull romanus pontifex ( January 8th , 1455 ) , which categorically commended the crusading inspiration of the Infante Dom Henrique and his desire to reach the mysterious Christian potentate ( s ) of the Indies by circumnavigating Africa . this bull also recognized the commercial motive inherent in Portuguese expansion by granting the King of Portugal and his successors the monopoly of the trade with the inhabitants of the newly discovered regions , subject to the proviso that the sale of war material to the enemies of the faith was forbidden . finally , it may be mentioned that as the Portuguese pushed their exploratory voyages down the west coast of Africa , they added the acquisition of negro slaves to that of Guinea gold , and the search for spices to the quest for Prester John . the spices , however , only appear as a major motive after the death of Prince Henry in 1460 , by which time the west African slave-trade was an established fact . the Portuguese voyages of discovery and trade down the west coast of Africa did not really get going until Cape Bojador ( or , more probably , Cape Juby , which was then apparently known by the former name ) was rounded in 1434 , after many futile efforts . the voyages then continued systematically , and a great spurt of progress was made during the eight-year regency ( 1440-48 ) of Dom Pedro , elder brother of the better publicized Dom Henrique , belatedly and somewhat inappropriately named the navigator . prior to his assumption of the regency , Dom Pedro had been violently critical of the policy of holding Ceuta , and had shown no particular interest in the voyages of discovery patronized by his brother . but once in power , as so often happens , Dom Pedro adopted wholeheartedly some of the policies that he had previously criticized , or to which he had been indifferent . all talk of abandoning Ceuta in exchange for the freedom of his youngest brother , Dom Fernando ( who had been held as a prisoner by the Moors since a disastrous attack on Tangier in 1437 ) , was dropped , and Dom Pedro actively backed the voyages of discovery and the colonization of the Atlantic islands . nevertheless , Dom Henrique &apos;s share in these twin enterprises was the more important in the long run . the voyages themselves , and the colonization of Madeira and the Azores , which began soon after their discovery - or re-discovery - in 1419-27 were largely financed from the revenues of the military order of Christ , of which Dom Henrique was the administrator and governor ( but not the grand master as is often stated ) from 1420 until his death forty years later . some of the leading Lisbon merchants also had a hand in financing and organizing these voyages . from 1470 to 1475 they were leased on the basis of a monopoly contract to a certain Fern&amp;atilde;o Gomes , under whose administration a large stretch of the Guinea coast was opened up to Portuguese enterprise and trade . it is still uncertain how much was directly due to government initiative and to resources supplied by the crown or by the order of Christ , and how much was due to private enterprise , or to both the crown and the merchant-adventurers acting in conjunction . but it can be said without undue simplification that right from the beginning , the planning , organization , and financing of these voyages owed a great deal to intelligent government initiative and support , as personified in the activities of Dom Henrique , Dom Pedro , and , above all , of King Dom Jo&amp;atilde;o 2 in the final stages ( 1481-95 ) . in other words , as C R Beazley pointed out over sixty years ago , Prince Henry &apos;s achievement was that he altered the conditions of maritime exploration by giving permanence , organization , and governmental support to a movement which had up to this time proved disappointing for lack of those very means . it was this steady government support that gave the Portuguese the edge over their Spanish neighbours and rivals , who for long contested the papal awards that granted a monopoly of the west African coastal trade to the former . but save during the years 1475-1480 , when the Spanish adventurers made determined but unsuccessful attempts to secure the lion &apos;s share of the Guinea trade for themselves , the Spaniards did not receive the same consistent and energetic support from their rulers as did the Portuguese from theirs . moreover , for much of the fifteenth century , Spain &apos;s cereal and financial problems were less acute than were those of Portugal , and therefore the Spaniards had not the same economic incentives to seek new lands to conquer or to exploit . finally , the existence of the Moorish kingdom of Granada on Andalusian soil , the prior commitments of the crown of Aragon in the Mediterranean , and the need to strengthen the crown of Castile against unruly vassals at home , provided powerful distractions that were not present to the same extent in Portugal . the actual voyages down the barren and featureless Saharan coast presented no exceptional difficulties to experienced seamen , other than the legendary but none the less real terrors of the unknown . these latter included the common , though not universal , belief that the torrid zone was too hot to support life , and that the Mar Tenebroso , or sea of darkness south of Cape Nun , was too shallow and too dangerous for navigation . 