The blooming prosperity of Zen was over towards the end of the Southern Sung dynasty (1127-1279), when it began to fade, not being bitten by the frost of oppression from without, but being weakened by rottenness within. As early as the Sung dynasty (960-1126) the worship of Buddha Amitabha[FN#58] stealthily found its way among Zen believers, who could not fully realize the Spirit of Shakya Muni, and to satisfy these people the amalgamation of the two faiths was attempted by some Zen masters.[FN#59] [FN#58] The faith is based on Larger Sukhavati-vyuha, Smaller Sukhavati-vyuha, and Amitayus-dhyana-sutra. It was taught in India by Acvaghosa, Nagariuna, and Vasubandhu. In China Hwui Yuen (E-on, died in A.D. 416), Tan Lwan (Don-ran, died in 542), Tao Choh (Do-shaku), and Shen Tao (Zen-do) (both of whom lived about 600-650), chiefly taught the doctrine. It made an extraordinary progress in Japan, and differentiated itself into several sects, of which Jodo Shu and Shin Shu are the strongest. [FN#59] It is beyond all doubt that Poh Loh Tien (Haku-raku-ten) practised Zen, but at the same time believed in Amitabha; so also Su Shih (So-shoku), a most noted Zen practiser, worshipped the same Buddha, Yang Kieh (Yo-keteu), who carried a picture of Amitabha wherever he went and worshipped it, seems to have thought there is nothing incompatible between Zen and his faith. The foremost of those Zen masters of the Sung dynasty that attempted the amalgamation is Yung Ming (Yo-myo, died in 975), who reconciled Zen with the worship of Amitabha in his Wan Shen Tung Kwei Tsih (Man-zen-do-ki-shu) and Si Ngan Yan Shan Fu (Sei-an-yo-sin-fu). He was followed by Tsing Tsz (Jo-ji) and Chan Hieh (Shin-ketsu, lived about 1151), the former of whom wrote Kwei Yuen Chih Chi (Ki-gen-jiki-shi), and the latter Tsing Tu Sin Yao (Jo-do-sin-yo), in order to further the tendency. In the Yuen dynasty Chung Fung (Chu-ho, died in 1323) encouraged the adoration of Amitabha, together with the practice of Zen, in his poetical composition (Kwan-shu-jo-go). In the Ming dynasty Yun Si (Un-sei, died in 1615), the author of Shen Kwan Tseh Tsin (Zen-kwan-saku-shin) and other numerous works, writing a commentary on Sukhavati-vyuha-sutra, brought the amalgamation to its height. Ku Shan (Ku-zan, died in 1657), a Zen historian and author, and his prominent disciple Wei Lin (E-rin), axe well known as the amalgamators. Yun Ming declared that those who practise Zen, but have no faith in Amitabha, go astray in nine cases out of ten; that those who do not practise Zen, but believe in Amitabha, are saved, one and all; that those who practise Zen, and have the faith in Amitabha, are like the tiger provided with wings; and that for those who have no faith in Amitabha, nor practise Zen, there exist the iron floor and the copper pillars in Hell. Ku Shan said that some practise Zen in order to attain Enlightenment, while others pray Amitabha for salvation; that if they were sincere