Catholic Church Law, Structure, and Governance

I forgot to give an asnwer to the question posed in the first, welcome, message. The image is the first page of Gratian’s Decretum, Gratian’s great contribution to the law of the Church. I attached another version of the same page from a different manuscript to this post.

The Decretum begins with:

Humanum genus duobus regitur, naturali videlicet iure et moribus. Ius naturae est quod in lege et evangelio continetur, quo quisque iubetur alii facere, quod sibi uult fieri, et prohibetur alii inferre, quod sibi nolit fieri. Unde Christus in evangelio: “Omnia quecunque vultis ut faciant vobis homines, et vos eadem facite illis. Haec est enim lex et prophetae.”

which means:

The human race is ruled by two [principles], the first is constituted natural law and by long standing custom. The law of nature is that which is contained in the Gospel and in the laws, that is to do to others what one would have done to one’s self and prohibits doing to others what one would not like done to one’s self. Thus Christ in the Gospel [said] “All that you want other men to do to you, you do to them. This is the law and the prophets”

[translation mine.]