Lastly, the depopulation caused by the terrible diseases which visited Europe in the century preceding the Moslem conquest aided greatly in destroying the empire. The prevalence of Black Death or Plague killed in the Balkan peninsula and especially in the towns hundreds of thousands and possibly millions of the population. In 1347 this scourge, probably the most deadly form of epidemic that has ever afflicted humanity, made its appearance in Eastern Europe. The cities of the empire contained large populations crowded together, and their normal population was increased by many fugitives. These crowded cities, with their defective sanitary arrangements and poverty-stricken inhabitants, offered a favourable soil for a rich harvest of death. The disease had followed the coasts from the Black Sea, where, says Cantacuzenus, it had carried off nearly all the inhabitants. At Constantinople it raged during two years, one of its first victims being the eldest son of Cantacuzenus himself.[170] Rich as well as poor succumbed to it. What proportion of the inhabitants of the city died it is impossible to say, but, judging by what is known of its effect elsewhere, we should probably not be wrong in suggesting that half the people perished. But its ravages were not confined to the towns, and from one end of the Balkan peninsula to the other it swept the country in repeated visitations and probably carried off nearly the same proportion of inhabitants.[171] Cantacuzenus, in a vivid description of the disease, adds that the saddest feature about it was the feeling of hopelessness and despair which it left behind. The first visitation of the disease continued during two years in the capital. In 1348 it spread throughout the empire. We have seen that in 1352 the victorious Venetian and Spanish fleets dared not venture to attack Galata for fear that their crews would be attacked by the malady. It raged in Asia Minor as fiercely as in Europe. Trebizond was ruined. The Turks themselves suffered severely. Between its entrance into Europe and 1364 the Morea had three visitations, and what remained of the Greek population became panic-stricken. Further north, at Yanina its ravages were equally terrible. In 1368 so many men died that Thomas, governor of the city, forced their widows to marry Serbians whom he had induced or compelled to enter the city for that purpose. A further outbreak seven years later took place in the same city, and among its victims was Thomas’s own daughter. During the same period Arta, which adjoins the ancient Cyzicus, suffered severely. It is useless for our purpose to inquire whether Black Death and Plague were identical, but one or the other continued to depopulate town and country. We have seen it at Ferrara in 1438, but in the interval since it first made its appearance it had visited the capital on seven different occasions, the latest being in 1431 when the whole country from Constantinople to Cape Matapan suffered severely.[172]