The reign of Wu-tsung (1506-21) was favourable to Buddhism. In 1507 40,000 men became monks, either Buddhist or Taoist. The Emperor is said to have been learned in Buddhist literature and to have known Sanskrit[699] as well as Mongol and Arabic, but he was in the hands of a band of eunuchs, who were known as the eight tigers. In 1515 he sent an embassy to Tibet with the object of inducing the Grand Lama to visit Peking, but the invitation was refused and the Tibetans expelled the mission with force. The next Emperor, Shih-T'sung (1522-66), inclined to Taoism rather than Buddhism. He ordered the images of Buddha in the Forbidden City to be destroyed, but still appears to have taken part in Buddhist ceremonies at different periods of his reign. Wan Li (1573-1620), celebrated in the annals of porcelain manufacture, showed some favour to Buddhism. He repaired many buildings at P'u-t'o and distributed copies of the Tripitaka to the monasteries of his Empire. In his edicts occurs the saying that Confucianism and Buddhism are like the two wings of a bird: each requires the co-operation of the other. European missionaries first arrived during the sixteenth century, and, had the Catholic Church been more flexible, China might perhaps have recognized Christianity, not as the only true religion but as standing on the same footing as Buddhism and Taoism. The polemics of the early missionaries imply that they regarded Buddhism as their chief rival. Thus Ricci had a public controversy with a bonze at Hang-Chou, and his principal pupil Hsü Kuang-Ch'i[700] wrote a tract entitled "The errors of the Buddhists exposed." Replies to these attacks are preserved in the writings of the distinguished Buddhist priest Shen Chu-Hung[701].