Other sovereigns hastened to pay their respects to the new Emperor, and Charlemagne received several embassies in search of alliance from Haroun al-Raschid, the Caliph of Bagdad. Haroun al-Raschid ruled over a mighty empire stretching from Persia to Egypt, and thence along the North African coast to the Strait of Gibraltar. On one occasion he sent Charlemagne a present of a wonderful water-clock that, as it struck the hour of twelve, opened as many windows, through which armed horsemen rode forth and back again. Far more exciting in Western eyes was the unhappy elephant that for nine years remained the glory of the imperial court at Aachen. Its death, when they were about to lead it forth on an expedition against the northern tribes of Germany, is noted sadly in the national annals. Rulers less fortunate than Haroun al-Raschid sought not so much the friendship of the Western Emperor as his protection, and through his influence exiled kings of Wessex and Northumberland were able to recover their thrones. Most significant tribute of all to the honour in which Charlemagne’s name was held was the petition of the Patriarch of Jerusalem that he would come and rescue Christ’s city from the infidel. The message was accompanied by a banner and the keys of the Holy Sepulchre; but Charlemagne, though deeply moved by such a call to the defence of Christendom, knew that the campaign was beyond his power and put it from him. Were there not infidels to be subdued within the boundaries of his own Empire, fierce Saxon tribes that year after year made mock both of the sovereignty of the Franks and their religion? The Saxons lived amongst the ranges of low hills between the Rhine and the Elbe. By the end of the eighth century, when other Teutonic races such as the Franks and the Bavarians had yielded to the civilizing influence of Christianity, they still cherished their old beliefs in the gods of nature and offered sacrifices to spirits dwelling in groves and fountains. The chief object of their worship was a huge tree trunk that they kept hidden in the heart of a forest, their priests declaring that the whole Heavens rested upon it. This _Irminsul_, or ‘All-supporting pillar’, was the bond between one group of Saxons and another that led them to rally round their chiefs when any foreign army appeared on their soil; though, if at peace with the rest of the world, they would fight amongst themselves for sheer love of battle. [Sidenote: St. Boniface] A part of the Saxon race had settled in the island of Britain, when the Roman authority weakened at the break-up of the Empire; and amongst the descendants of these settlers were some Christian priests who determined to carry the Gospel to the heathen tribes of Germany, men and women of their own race but still living in spiritual darkness. The most famous of these missionaries was St. Winifrith, or St. Boniface according to the Latin version of his name that means, ‘He who brings peace.’