Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Councils of Ancyra, Gangra, Neocæsarea, Antioch and Laodicea, which Canons were Accepted and Received by the Ecumenical Synods.: Canon LIV

Canon LIV.

Members of the priesthood and of the clergy must not witness the plays at weddings or banquets; but, before the players enter, they must rise and depart.

Notes.

Ancient Epitome of Canon LIV.

Priests and clerics should leave before the play.

Aristenus.

Christians are admonished to feast modestly when they go to weddings and not to dance nor βαλλίζειν , that is to clap their hands and make a noise with them.  For this is unworthy of the Christian standing.  But consecrated persons must not see the play at weddings, but before the thymelici begin, they must go out.

Compare with this Canons XXIV. and LI., of the Synod in Trullo.

This canon is found in the Corpus Juris Canonici, Gratian’s Decretum, Pars III., De Consecrat. Dist. v., can. xxxvij.