Nearer home the Order found less favour. In Poland, for instance, that had at first welcomed the Knights as a bulwark against northern barbarism, the unpleasant knowledge gradually dawned that the crusaders, by securing the territory of Livonia, Curland, and Prussia, had cut her off from a lucrative sea-trade.
Poland was the most easterly of those states that in mediaeval times owned a nominal allegiance to Holy Roman Emperors. She had received her Christianity from Rome, and was thus drawn into the network of western life—unlike Russia, or the kingdom of Rus as it was called, that was converted by missionaries from Constantinople, and whose princes and dukes were subject to Mongol overlords in Siberia from the middle of the thirteenth to the middle of the fifteenth century.
The Poles were brave, intensely devoted to their race, persistent in their enmities, and in none more than in their dislike of the German Knights, whose military genius and discipline had so often thwarted their ambitions. Quarrels and wars were continuous, but the most mortal wound dealt by the Poles was the result not of a victory but of a marriage alliance.
In 1387, soon after the death of Louis ‘the Great’, who had been King of both Hungary and Poland, the Poles offered their crown to Duke Jagello of Lithuania; on the condition that he would marry one of Louis’s daughters and become a Christian. The temptation of a kingdom soon overcame Jagello’s religious scruples, so that he cast away his old gods and was baptized as Ladislas V, becoming the founder of the Jagellan dynasty, that continued on the thrones of Poland and Lithuania right through the Middle Ages.
The conversion of the Lithuanians, who, whatever their beliefs, were driven at the spear-point to accept Jagello’s new faith, completely undermined the position of the Teutonic Order that, surrounded by Christian neighbours, had no longer a crusade to justify its claims. Popes ceased to send their blessing to the Grand Master, and talked instead of the possibilities of suppression; while tales of immorality and avarice such as had pursued the Templars were everywhere whispered into willing ears.
Within their own territory also the influence of the Knights was waning; for the very nature of their vows made their rule merely a military domination; and, once the fear of heathen invasion had been removed, German colonists began to resent this. Condemned to celibacy, the Knights could train up no hereditary successors in sympathy from childhood with the needs of the Baltic province; but, as they grew old and died, they must yield place instead to recruits from distant parts of Germany, who could only learn anew by their own experience the manners and traditions of those whom they governed.
In the stress of these new conditions the good work that the Teutonic Order had done in saving North Germany from barbarism was forgotten. Weakened by disaffection within her own state, she fell an inevitable victim to Polish enmity, and at the battle of Tannenberg her Grand Master and many of her leading Knights were slain. The daring and determination of those who remained prevented the full fruits of this victory from being reaped until 1466, when, by the Treaty of Thorn, Poland received the whole of western Prussia, including the important town of Danzig, that gave her the long-coveted control of the Vistula and a Baltic seaport, beside hemming her enemies into the narrow strip of eastern Prussia.
Louis ‘the Great’
Poland’s southern neighbour was the kingdom of Hungary, with which she had been for a short time united under Louis ‘the Great’, ‘the Banner-bearer of the Church’ as he was styled by a grateful Pope for his victories over the Mahometans. Besides fighting against the Turks, Louis had other military irons in the fire. One of his ambitions was to dominate Eastern Europe, and with this object he was continually attacking and weakening the Serbian Empire, that appeared likely to be his chief rival. He also fought with the Venetians for the mastery of the Dalmatian coast, while we shall see in a later chapter that he aimed at becoming King of Naples on the murder of his brother Prince Andrew, husband of Joanna I.