《魏书·列传·卷七十》
皇帝令祖莹与录尚书事长孙稚、侍中元孚掌管制造各种乐器，三年就制造完成，具体情况记在《乐志》。
敕莹与录尚书事长孙稚、侍中元孚典造金石雅乐，三载乃就，事在《乐志》。
The emperor ordered Zuying to take charge of manufacturing various musical instruments with the Recording Minister of State Affairs, Changsunzhi, and the Imperial Secretary Yuan Fu. The work was completed in three years and the details are recorded in the Annals of Music.