is not certain whether the year was considered at
Constantinople as beginning with September before the separation of the
Eastern and Western empires.

At the commencement of our era there had elapsed 5508 years and four
months of the era of Constantinople. Hence the first eight months of the
Christian year 1 coincide with the Constantinopolitan year 5509, while
the last four months belong to the year 5510. In order, therefore, to
find the year of Christ corresponding to any given year in the era of
Constantinople, we have the following rule: If the event took place
between the 1st of January and the end of August subtract 5508 from the
given year; but if it happened between the 1st of September and the end
of the year, subtract 5509.

_Era of Alexandria._--The chronological computation of Julius Africanus
was adopted by the Christians of Alexandria, who accordingly reckoned
5500 years from the creation of Adam to the birth of Christ. But in
reducing Alexandrian dates to the common era it must be observed that
Julius Africanus placed the epoch of the Incarnation three years earlier
than it is placed in the usual reckoning, so that the initial day of the
Christian era fell in the year 5503 of the Alexandrian era. This
correspondence, however, continued only from the introduction of the era
till the accession of Diocletian, when an alteration was made by
dropping ten years in the Alexandrian account. Diocletian ascended the
imperial throne in the year of Christ 284. According to the Alexandrian
computation, this was the year 5787 of the world, and 287 of the
Incarnation; but on this occasion ten years were omitted, and that year
was thenceforth called the year 5777 of the world, and 277 of the
Incarnation. There are, consequently, two distinct eras of Alexandria,
the one being used before and the other after the accession of
Diocletian. It is not known for what reason the alteration was made; but
it is conjectured that it was for the purpose of causing a new
revolution of the cycle of nineteen years (which was introduced into the
ecclesiastical computation about this time by Anatolius, bishop of
Hierapolis) to begin with the first year of the reign of Diocletian. In
fact, 5777 being divided by 19 leaves 1 for the year of the cycle. The
Alexandrian era continued to be followed by the Copts in the 15th
century, and is said to be still used in Abyssinia.

Dates expressed according to this era are reduced to the common era