In process of time, however, the custom of dating by the regnal year of the king became general.
It is significant in this connexion that it was under Adrian (c. 774) that the papal chancery ceased to date by the regnal years of the Eastern emperor and substituted that of the pontificate.
From the Middle Kingdom onward to the Roman period, the dates upon Egyptian documents are given in regnal years.
The question arises from what point these regnal dates were calculated.
Historical.As to absolute chronology, the assigning of a regnal year to a definite date B.C. is clear enough (except in occasional detail) from the conquest by Alexander onwards.