 It was only in 804 at the age of 30 or 31 that Kūkai was thus officially ordained so that he could travel with an official government embassy to China. He travelled to Ch’ang-an, the great cosmopolitan capital of the T’ang (Tang) dynasty, where he resided for thirty months. During this period, he studied Indian Buddhism, Hindu teachings, and Sanskrit with two Indian monks. But more significantly he met Hui-kuo (Huiguo; Jpn: Keika) (746–805), the seventh patriarch of Chen-yen (Zhenyan; Jpn: Shingon; Skrt: Mantrayāna) Buddhism, from whom he received initiation into the two lineages of Chen-yen esoteric Buddhism, one centered around the Vajradhātu (Diamond realm) mandala based on the Vajraśekhara Sūtra (“Adamantine {or Diamond} Pinnacle scripture”) and the other focussing upon the Garbha (Womb) mandala based on the Mahāvairocana Sūtra. Kūkai’s accomplishment during his stay in China is phenomenal in that not only did he manage to succeed Hui-kuo in becoming the eighth patriarch of esoteric Buddhism, he also managed to study Sanskrit, Chinese poetry and calligraphy, and various other minor arts.