Zhè xiàng chuántǒng fāyuán yú Tángdài de gōngtíng lǐyí.
This tradition began in the court ceremonies of the Tang dynasty.
Tips
grammar
Almost always paired with 于 and a place, never with a direct object after it. The matching noun is 发源地, the place something started.
usage
It keeps the river picture, water leaving its spring, so it suits rivers and anything traceable to one place. For beginnings in general, including origins in time, use 起源.