Where Byzantine influences prevailed the years were generally numbered from the beginning of the world ().This era was calculated from 1 September, and the birth of Christ, which is the point of departure of our present chronology, took place in the year 5509 of the Byzantine system.
As a continuous system of year enumeration the oldest era in practical use appears to have been that known as the "Era of the Martyrs" or "of Diocletian" () was in familiar use in Spain from the fifth century down to late in the Middle Ages.
It adds about thirty-eight years to the ordinary numbering of the Christian Era.
xxxiii) that "of this series the first five though all more or less dated, whether by the month or the regnal year, or by the Indiction, or by all these at once, have not the Anno Domini.
On the other hand, the last three agree in using the Christian Era and from this time the practice is continuous.
"Those who have seen it say that the document which John brought does not bear the day or the indiction . Even down to the beginning of the twelfth century not only royal and imperial letters but even charters (), properly so called, were occasionally through the carelessness of officials sent out without a date.
(Bresslau, Handbuch, I, 891.) In this matter the Italian chancery officials seem to have been much more careful than those of the rest of Europe.In reckoning the beginning and consequently the determining-point of the indiction-cycles four different systems were adopted: the .Concurrently with the year of the indiction it was customary both in papal and imperial documents to mention the regnal year of the pope or emperor.It is in any case certain that neither in the papal chancery nor in that of the Western Empire was the system introduced until considerably later.In the empire it only became general in the latter part of the ninth century, while although it occurs occasionally in papal documents of the time of John XIII (965-972), it was not the rule before the twelfth century.It is only from about the year 679 that we are able to appeal to English charters of indisputable authenticity.