Ancient Craft Masons
A.L., Anno Lucius which is Latin and translates “Year of Light,” found by adding 4,000 to the modern year.
1:3 – And God said, Let there be light: and there was light.
A.M, Latin for Anno Mundi, “In the year of the World” date the same as Craft Masons, except for the use of the Jewish Chronology. It found by adding 3760 to the common time.
Royal Arch Masons
A.I., latin for Anno Inventionis,which means “In the year of Discovery.” This date is from the year the second temple was commended by Zerubbabel. This adds 530 to the common time.
Royal and Select Masters or Cryptic Masons
A.D., Anno Depositionis Latin, which means “In the year of the Deposit”. This date is from the year in which the Temple of Solomon was completed. If you 1000 to the common time you will find it.
The Order of High Priesthood
A.B., Anno Bonefacio is Latin for In The Year of the Blessing. Calculated from the year of the blessing of Abraham by the High Priest, Melchizedek as referenced in Genesis 14:18-20. Add the year of the blessing, 1913 B.C.E. + the current year.
Albert Mackey references to what we now call our current year as the “Vulgar” era.