Isaac Newton died in 1727, though his gravestone says 1726

Isaac Newton died at Kensington, near London, on 31 March 1727 by the modern calendar, aged 84, and was buried in Westminster Abbey eight days later.

Yet the Latin inscription on Newton’s grave in the Abbey nave gives his death as 20 March MDCCXXVI, that is, 1726. It is not a mistake. England still used the Julian calendar, which by then ran 11 days behind the Gregorian calendar used in most of western Europe, and its legal year did not begin on 1 January but on 25 March, Lady Day.

A death on 20 March therefore fell in the last week of 1726 as Newton’s contemporaries counted. Britain did not switch until 1752, when 11 days were dropped and New Year moved to 1 January. So “20 March 1726”, “20 March 1727” and “31 March 1727” all describe the same day.

His funeral was a state occasion in all but name. His body lay in state in the Abbey’s Jerusalem Chamber, the Lord Chancellor, two dukes and three earls carried the pall, and most of the Fellows of the Royal Society followed the coffin. Those Fellows had been led by Newton for a long time. He was elected President of the Royal Society in 1703 and re-elected every year until his death, a run of 24 years. Some accounts, including the Abbey’s own page, say 1705, the year he was knighted, but the Society’s records give 1703.

His monument beside the grave, sculpted by Michael Rysbrack to a design by William Kent and finished in 1730, shows boys with a prism, a telescope and coins from the Royal Mint, which Newton ran in his later years. Alexander Pope wrote an epitaph for it, “Nature and Nature’s laws lay hid in night: God said, Let Newton be! and all was light”, but the couplet was not allowed on the monument.