In the first 200 years of Christian history, no mention is made of the calendar date of Jesus' birth. Not until the year 336 do we find the first mention of a celebration of His birth.
Why this omission? In the case of the Church fathers, the reason is that, during the three centuries after Christ's life on earth, the event considered most worthy of commemoration was the date of His death. In comparison, the date of His birth was considered insignificant. As the Encyclopedia Americana explains, "Christmas... was, according to many authorities, not celebrated in the first centuries of the Christian church, as the Christian usage in general was to celebrate the death of remarkable persons rather than their birth..." (1944 edition, "Christmas").
http://www.new-life.net/chrtms10.htm
about Armenians being monophysite... :klubnik: