Church of Martyrs - After the martyrdom of St. Mark, the Coptic Church faced severe persecutions. The seventh persecution inflamed by emperor Diocletian; his reign (284-305) is considered by the Copts as the age of persecution. Under Maximin Daia (305-313), his successor in the East, the massacre continued for eight years of systematic killing. This could account for tremendous number of martyrs. So profound was the impression of the persecution of Diocletian on Coptic life and thought that the Copts decided to adopt for church use a calendar of the martyrs, the “Anno Martyri”. The first year of that calendar was 284 A.D., the year of the disastrous accession of Diocletian.
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Church of Martyrs - After the martyrdom of St. Mark, the Coptic Church faced severe persecutions. The seventh persecution inflamed by emperor Diocletian; his reign (284-305) is considered by the Copts as the age of persecution. Under Maximin Daia (305-313), his successor in the East, the massacre continued for eight years of systematic killing. This could account for tremendous number of martyrs. So profound was the impression of the persecution of Diocletian on Coptic life and thought that the Copts decided to adopt for church use a calendar of the martyrs, the “Anno Martyri”. The first year of that calendar was 284 A.D., the year of the disastrous accession of Diocletian.
From: http://www.lacopts.org/highlights-of-the-coptic-orthodox-church
You might also want to read this article: http://www.stmarystlouis.bizland.com/church of martyrs Bishop Youssef.htm
Sorry if this is all basic to you, I'm not sure how much you know but let me know and I'll find some more stuff :)
God bless,
Matthew