The most magnificent of all the palaces was that of the Khalif Moktader-billah, called the “House of the Tree,”[269] and seated in a wide extent of gardens. In the middle of the vestibule, near two large basins of water, stood two trees of gold and silver, each having eighteen branches, and a great number of smaller boughs. One of these bore fruit and birds, whose variegated plumage was imitated with different precious stones, and which gave forth melodious sounds, by means of the motion of the branches, produced by a mechanical contrivance. On the other tree were fifteen figures of cavaliers, dressed in pearls and gold, with drawn swords, which, on a signal being given, moved in concert. In this palace, the Khalif Moktader gave audience to the ambassadors of the Greek emperor, Theophilus,[270] and astonished them with the numbers of his army, and the splendour of his court.[271] A hundred and sixty thousand men stood in their ranks before the palace; the pages glittered in golden girdles; seven thousand eunuchs, three thousand of whom were white, the rest black, surrounded the entrance; and, immediately at the gate, were seven hundred chamberlains. On the Tigris floated gilded barks and gondolas, decorated with silken flags and streamers. The walls of the palace were hung with thirty-eight thousand carpets, twelve thousand five hundred of which were of gold tissue; and twenty-two thousand pieces of rich stuff covered the floors. A hundred lions, held by their keepers with golden chains, roared in concert with the sound of fifes and drums, the clang of the trumpets, and the thundering of the tamtam.[272] The entrance to the audience chamber was concealed by a black silk curtain; and no one could pass the threshold, without kissing the black stone of which it was formed, like the pilgrims at Mecca.[273] Behind the black curtain, on a throne seven ells high, sat the khalif, habited in the black mantle (_borda_) of the prophet, girded with his sword, and holding his staff in his hand as a sceptre. Ambassadors, and even princes, who received investiture, kissed the ground in front of the throne, and approached, conducted by the vizier and an interpreter, and were then honoured with a habit of ceremony (_khalaat_), and presents. So Togrul-beg, the founder of the Seljuks, on receiving investiture from the Khalif Kaim-Biemrillah, was dressed in seven caftans, one over the other, and presented with seven slaves, from the several different states forming the khalifat. He received two turbans, two sabres, and two standards, in token of being invested with the sovereignty of the east and the west.[274]