Antipope Hippolytus 
The Apostolic Tradition of Hippolytus [EPUB ebook] 

The early Church Orders were systematic manuals of disciplinary and liturgical rules for which the collective authority of the whole apostolate was claimed. They made their appearance in the second century, grew to considerable dimensions in the third, and reached their fullest development toward the end of the fourth century. They are sources of importance for our knowledge of the inner life of the church, and they were influential factors in the formation of the later canon law.