Old Style vs New Style Dates, and Regnal Years

Two separate dating problems tend to trip people up in English documents before the mid-eighteenth century, and they often get tangled together because they overlap in time. This guide takes them one at a time: first the calendar itself — when the year began, and the 1752 switch from Julian to Gregorian dating — and then regnal years, the "in the fourth year of the reign of..." formula you will meet constantly in legal and official documents.

Part One: Old Style and New Style Dates

When did the year actually begin?

From the thirteenth century until 1752, the legal and civil year in England began on 25 March — Lady Day, the feast of the Annunciation — not on 1 January. So a document dated, in its own words, "10 February 1719" was written in what we would now call February 1720: the writer's "1719" would not tick over to "1720" until 25 March.

This is separate from — but easily confused with — the Julian/Gregorian calendar question below. A document can have an Old Style year-start problem, an Old Style/New Style day-count problem, or both at once.

The 1752 calendar change

By the eighteenth century, the Julian calendar Britain was still using had drifted eleven days behind the Gregorian calendar most of Catholic Europe had adopted back in 1582. The Calendar (New Style) Act 1750 fixed this in two moves:

• It reset the start of the legal year to 1 January, beginning with 1752 (so 1751 was a short year, running only from 25 March to 31 December).
• It aligned the calendar itself with the rest of Europe by omitting eleven days: Wednesday 2 September 1752 was directly followed by Thursday 14 September 1752.

Scotland had already moved its own start-of-year to 1 January back in 1600, but kept the Julian day-count in step with England until the same 1752 reform brought the whole of Britain onto the Gregorian calendar together.

"Old Style" and "New Style" — what the labels mean

Historians use OS (Old Style) for the Julian-calendar dating used in England before 1752, and NS (New Style) for the Gregorian dating used on the Continent throughout, and in Britain from 1752 onward. The gap between the two was ten days until 1700, and eleven days from 1700 onward.

Part Two: Regnal Years

Before the mid-twentieth century, English official, legal and parliamentary documents were routinely dated not by calendar year at all, but by the year of the reigning monarch — "the fourth year of the reign of King George the Second," commonly abbreviated in print as something like "4 Geo. 2." This is the regnal year, and it runs on its own clock, quite separate from either the calendar year or the legal year discussed above.

How regnal years work

A monarch's first regnal year begins on the exact date of their accession — not 1 January, not Lady Day, but the specific day they became sovereign — and each subsequent regnal year begins on the anniversary of that date. King George III, for example, acceded on 25 October 1760; his second regnal year therefore ran from 25 October 1761, his third from 25 October 1762, and so on. Because every monarch acceded on a different date, the "regnal year start date" is different for every reign, and you cannot use one reign's pattern to guess at another's.

The Charles II trap

This is the one that catches people out. Charles II did not actually become king until the Restoration, on 29 May 1660 — but his regnal years are officially counted from 30 January 1649, the day his father Charles I was executed. The eleven years of the Commonwealth and Protectorate were struck from the official legal record entirely, as though Charles II had been reigning, uncrowned, throughout. The practical effect: when the Restoration actually happened in May 1660, the official record regarded it as already being in the 12th year of his reign. If you see a document dated in a low regnal year of Charles II — "1 Car. 2" or "2 Car. 2" — and the content plainly describes events of 1660 or later, this is why: those numbers correspond to 1649–1651, not to the start of his actual rule.

Regnal years around the 1752 calendar change

The 1752 reform also had to account for the eleven missing days of September. George II's 26th regnal year, which had begun on 11 June 1752, was extended by eleven days so that it still ran a full year — meaning that from 1753 onward, his regnal year began on 22 June rather than 11 June. This kind of small adjustment around 1752 is worth watching for in any document from that specific window.

Regnal year start dates for the monarchs most often seen in probate, Chancery and manorial documents

A note on legal terms and law years

You will also see documents dated only by law term and regnal year — "Michaelmas term, 5 George II" — with no specific day given. The four law terms (Hilary, Easter, Trinity and Michaelmas) were the periods when the higher courts sat, and a great deal of Chancery and Common Pleas business is dated this loosely rather than to a specific calendar day. If precision matters, the regnal year narrows things to a roughly twelve-month window; the term narrows it further to a few weeks within that.

Putting It Together

A single document can involve all three of these conventions at once: a Lady-Day legal year, an Old Style Julian date, and a regnal year dated from a king's accession rather than his actual reign. When transcribing, the safest approach is always the same — record the date exactly as the document gives it, then add your own note translating it into a modern calendar date if that will help the reader. Never silently substitute one for the other.

Calendar and regnal year figures checked against the Calendar (New Style) Act 1750, and against the regnal year tables compiled from C. R. Cheney and Michael Jones, A Handbook of Dates for Students of British History (Royal Historical Society Guides and Handbooks No. 4, Cambridge University Press, revised ed. 2000), and Sweet & Maxwell's Guide to Law Reports and Statutes (4th ed., 1962). The regnal date for Charles II reflects the official legal fiction described in these sources, not his actual accession to power in 1660.