Adjective
Of or pertaining to the reign of a monarch; as, regnal years.
Source: Webster's dictionaryAll of these emperors, except Justinian, used imperial post-consular years for the years of their reign, along with their regnal years. Source: Internet
Furthermore, he was the first pope to add the regnal number "I", designating himself "the First". Source: Internet
However, he was traditionally considered the "last Roman Emperor" by 18th and 19th century western scholars and his overthrow by Odoacer used as the marking point between historical epochs, and as such he is usually included in regnal lists. Source: Internet
Howarth, p. 63; Judd, p. 135 Early reign Darlington Town Hall decorated for the Coronation, 1937 Albert assumed the regnal name "George VI" to emphasise continuity with his father and restore confidence in the monarchy. Source: Internet
He is the most recent pope to choose to retain his birth name as his regnal name upon his accession, as well as only the second and most recent pope to date to take the name "Marcellus" upon being elected. Source: Internet
His death occurred at some time between Nisan 1 of 848 BC and Tishri 1 of that same BC year, i.e. in the Judean regnal year 849/848 BC, which for calculation purposes can be taken as 849 BC. Source: Internet