The Order of the High Priesthood sometimes referred to as the Anointed Order of High Priesthood or the Order of Melchizedek is a "chair" degree that is conferred upon those who are or have served as Excellent High Priest for a Chapter of Royal Arch Masons.
The first authenticated record of this Order is to be found in the proceedings of the Grand Chapter of Ohio in 1828.
The Order of High Priesthood dates from the year of the blessing of Abraham by the high priest, Melchizedek, King Salem. It is called Anno Benedictionis (A.B.) - "In the year of Blessing" and adds 1913 to the common time. Therefore the year 2022 becomes 3935.
For this Melchizedek, King of Salem, priest of the most high GOD, who met Abraham returning from the slaughter of the kings, and blessed him; to whom also Abraham gave a tenth part of all, first being by interpretation, King of righteousness, and after that also, King of Salem, which is, King of peace; without father, without mother, without descent, having neither beginning of days, nor end of life, but made like unto the Son of GOD, abides a priest continually. Now consider how great this man was, unto whom even the patriarch Abraham gave the tenth of the spoils. And verily, they that are of the sons of Levi, who receive the office of the priesthood, have a commandment to take tithes of the people according to the law, that is, of their brethren, though they come out of the loins of Abraham. For he testifies, Thou art a priest forever after the order of Melchizedek. And inasmuch as not without an oath he was made priest. For those priests (under the Levitical law) were made without an oath; but this with an oath, by him that said unto him, the LORD has sworn, and will not repent, Thou art a priest forever according to the order of Melchizedek.