The Commandments of the Church (in this restricted sense) are moral and ecclesiastical, and as a particular code of precepts are necessarily broad in character and limited in number.
[5] As early as the time of Constantine I, especial insistence was put upon the obligation to hear Mass on Sundays and Holy Days, to receive the sacraments and to abstain from contracting marriage at certain seasons.
[5] According to a work written by Regino, the abbot of Prüm (d. 915), entitled Libri duo de synodalibus causis et disciplinis, the bishop should ask in his visitation:[5] "if anyone has not kept the fast of Lent, or of the ember-days, or of the rogations, or that which may have been appointed by the bishop for the staying of any plague; if there be any one who has not gone to Holy Communion three time in the year, that is at Easter, Pentecost and Christmas; if there be any one who has withheld tithes from God and His saints; if there be anyone so perverse and so alienated from God as not to come to Church at least on Sundays; if there be anyone who has not gone to confession once in the year, that is at the beginning of Lent, and has not done penance for his sins.
Thus in a book of tracts of the thirteenth century attributed to Pope Celestine V (though the authenticity of this work has been denied) a separate tractate is given to the precepts of the Church and is divided into four chapters, the first of which treats of fasting, the second of confession and paschal Communion, the third of interdicts on marriage, and the fourth of tithes.
[5] In the fourteenth century Ernest von Parduvitz, Archbishop of Prague, instructed his priests to explain in popular sermons the principal points of the catechism, the Our Father, the Creed, the Commandments of God and of the Church (Hafner, loc.