The history of tea in Japan has its earliest known references in a text written by a Buddhist monk in the 9th century. Tea became a drink of the religious classes in Japan when Japanese priests and envoys sent to China to learn about its culture brought tea back to Japan. The first form of tea brought from China was probably brick tea. Ancient recordings indicate the first batch of tea seeds were brought by a priest named Saicho in 805 AD and then by another named Kukai in 806 AD. It became a drink of the royal classes when Emperor Saga, the Japanese emperor in the early 9th century, encouraged the growth of tea plants. Seeds were then imported from China, and cultivation in Japan began.