Canon 37
That meetings of the bishops of each diocese should be held twice a year: on the fourth week of Pentecost and on October 12.
Twice a year let there be a Council of Bishops, and let them reason with each other about the dogmas of piety and resolve ecclesiastical disputes: the first time on the fourth week of Pentecost, and the second on the twelfth day of the month of Pervertean.
Greek original
Δεύτερον τοῦ ἔτους σύνοδος γινέσθω τῶν ἐπισκόπων, καὶ ἀνακρινέτωσαν ἀλλήλως τὰ δόγματα τῆς εὐσεβείας, καὶ τὰς ἐμπιπτούσας ἐκκλησιαστικάς ἀντιλογίας διαλυέτωσαν· ἅπαξ μέν, τῇ τετάρτῃ ἑβδομάδι τῆς Πεντηκοστῆς· δεύτερον δέ, Ὑπερβερεταίου δωδεκάτῃ.
Parallel canons
Ап.34IВс.5IIВс.2IVВс.19Трул.8VIIВс.6Антиох.20Лаод.40Карф.1873