This was the beginning of the actual schism between the Eastern and Western Churches that had been always alien in their outlook. In the ninth century the breach widened, for Pope Nicholas I supported a Patriarch, or Bishop of the Eastern Church, deposed by the Emperor and excommunicated his rival and successor, while subsequent disputes were rendered irreconcilable in the middle of the eleventh century when the Patriarch of Constantinople closed the Latin churches and convents in his diocese and publicly declared the views of Rome heretical.

Besides the Pope at Rome the Eastern Empire possessed other foes in Italy. Chief of these were the Normans, who, not content with acquiring Naples, had, under the leadership of Robert Guiscard and his son Bohemund, captured the famous port of Durazzo on the Adriatic and invaded Macedonia. From this province they were only evicted by Alexius Commenus after wearying campaigns of guerrilla warfare to which his military ability was better suited than to pitched battles or shock tactics.

The Venetian Republic

More subtly dangerous than either Pope or Normans was the commercial rivalry of the merchant cities of the Mediterranean, Pisa, Genoa, and Venice. It was Venice who from behind her barrier of islands had watched Attila the Hun lead away his armies in impotent rage.[13] It was Venice again who of the North Italian states successfully resisted the feudal domination of Western Emperors and kept her own form of republican government inviolate of external control. It was the young Venice, the ‘Queen of the Adriatic’ as her sons and daughters proudly called her, that could alone in her commercial splendour and arrogance compare with the dying glory of Constantinople.

Alexius Commenus in his struggles against Robert Guiscard had been compelled to call twice upon Venice for the assistance of her fleet; but he paid dearly for this alliance in the trading privileges he was forced to grant in Eastern waters. Wherever in the Orient Venetian merchants landed to exchange goods they were quick to establish a political footing; and the world mart on the Adriatic, into which poured the silks and dyes, the sugar and spices of Asia, built up under the rule of its ‘Doges’, or Dukes, a national as well as a commercial reputation.

In 1095 necessity spurred Alexius Commenus to appeal not merely to Venice for succour but to Pope Urban II and all the leading princes of Western Europe.

‘From Jerusalem to the Aegean,’ he wrote, ‘the Turkish hordes have mastered all: their galleys, sweeping the Black Sea and the Mediterranean, threaten the imperial city itself, which, if fall it must, had better fall into the hands of Latins than of Pagans.’

These Turks, or ‘Tartars’, to whom he referred, were the cause of the Eastern Empire’s sudden danger. Descendants of a Mongol race in central Asia, of which the Huns were also an offshoot, they turned their faces westward some centuries later than the ancestors of Attila, fired by the same love of battle and bloodshed and the same contempt for civilization. To them the wonderful Arabian kingdom, moulded by successive Caliphs of Bagdad out of Eastern art, luxury, and mysticism, held no charm save loot. Conquered Greece had endowed Rome with its culture, but the inheritance of Haroun al-Raschid bequeathed to its conquerors only the fighting creed of Islam.

Mahometans in faith, the Turkish armies, more dangerous than ever because more fanatical, swept over Persia, Syria, Palestine, and Asia Minor, subjugating Arabs and Christians until they came almost to the straits of the Bosporus. Here it was that they forced Alexius Commenus to realize his imminent danger and to turn to his enemies in Europe for the protection of his tottering Empire.

The Latins, or Christians of the West, to whom he appealed, had reasons enough of their own for answering him with ready promises of men and money. From the early days of the Church it had been the custom of pious folk, or of sinners anxious to expiate some crime, to set out in small companies to visit the Holy Places in Jerusalem where tradition held that Christ had preached, prayed, and suffered, that there they might give praise to God and seek His pardon. These ‘pilgrimages’, with their mixture of good comradeship, danger, and discomfort, had become very dear to the popular mind, and, if not encouraged by the Mahometan Arabs, had been at least tolerated. ‘Hospitals’, or sanctuaries, were built for the refreshment of weary or sick travellers, and pilgrims on the payment of a toll could wander practically where they chose.