Far beneath the lofty vaults of Salisbury Cathedral in the south of England, a mottled stone slab in the floor marks Thomas Lambert’s resting place with this cryptic inscription:

H[ic] S[epultus] E[st] (“Here lies…”)
the body of Tho[mas]
the sonn of Tho[mas]
Lambert gent[leman]
who was borne
May y[e] 13 An[no] Do[mini]
1683 & dyed Feb
19 the same year

What act of wizardry or—Great Scott!—time-traveling technology allowed this child to die before he was born? Alas, there is no magic to this story. The unspectacular answer is that Lambert died in 1684 and not 1683.

Yet the engraver did not make a mistake. For him and his contemporaries, February did indeed belong to “the same year” as that of the previous May.

The Old New Year

In 1684, the New Year in England and its colonies officially began on March 25, as it had for centuries and as it would for decades more until January 1, 1752, when a parliamentary “act for regulating the commencement of the year” went into effect.

Scholars, genealogists, and historical sleuths must therefore always adjust the year for dates between January 1 and March 24 that appear in English sources before the mid-18th century.

Take the example of Lady Dorothy Spencer (yes, of those Spencers). The ancestor of both Winston Churchill and The People’s Princess was entombed a mere six days after Lambert. A book published before 1752 gives her date of burial as “the 25th of February 1683,” while one published just after explains that “she died in 1684.”

Even those who come to Westminster Abbey to pay their respects to that stickler for precision, Isaac Newton, have some recalculating to do. His monument gives the date of his death as March 20, 1726. But as any authoritative biography will tell you, Newton died in 1727.

Confusion Abounds

Though 17th- and 18th-century gravestones in England can deceive the modern viewer, those in France do not. Most of Europe had followed Pope Gregory’s reforms of 1582 and adopted January 1 as the start of the New Year. But Protestant England, which had spent years and fought wars resisting papal authority, ignored Pope Gregory’s edict “for no other reason than it had been published by the Pope,” according to the Italian observer Gregorio Leti in 1684. The English were at that time unwilling to accept a Catholic cure for a calendrical malady that some also blamed on popery. “We presume it [starting the New Year in March] to have sprung from Romish Superstition,” explained a British magazine in 1708.

They were, in their way, correct. March 25 is the Feast of the Annunciation (known as Lady Day in England) which commemorates Gabriel’s announcement that Mary would give birth to Jesus Christ—as good a day as any to celebrate the New Year. Tuscans thought so, too, and continued to prefer March to January as the start of the year until 1750, when the Grand Duke made the switch to avoid “any confusion and difficulty in determining the time.”

Confusion could abound when sending letters between countries that were, legally, in different years. When Lady Dorothy’s father was ambassador to France, he would date his letters with fractions for clarity, writing the year, in one example, as “Feb 1641/0.” Others preferred to specify with abbreviations indicating a date in the “old style” (OS) or the “new style” (NS).

When the English adopted the “new style,” they made life easier for everyone (and fixed another significant error in the former calendar). But they also made sure a riddle like Thomas Lambert’s grave would not happen again.