佛祖統紀 2.38

2.38

四十年（戊辰）太子年十五歲。王會群臣諸小王仙人婆羅門等。皆悉雲集。至二月八日。以七寶器。盛四大海水。各各頂戴。傳授與王。灌太子頂。付七寶印。立為太子。時八國王。亦於是日同立太子（因果經）。

Fortieth year (wuchen): The Prince was fifteen years old. The King assembled his ministers, minor kings, ṛṣis, and brāhmaṇas, who all gathered like clouds. On the eighth day of the second month, using vessels of the seven treasures, they filled them with water from the four great oceans, each bearing them on their heads and transmitting them to the King. They anointed the Prince's crown, conferred the seven-jewel seal, and installed him as Crown Prince. At that time, eight kings of other realms also installed their crown princes on the same day (Sūtra on Cause and Effect).