Once in a leap year

Sir, – Patsy McGarry (In a Word, February 24th) credits Pope Gregory XIII with giving us an additional day (February 29th) in every fourth year. However, the origin of the “intercalary” day goes back to the introduction of the Julian calendar in 45 BC.

Far from adding February 29th to the calendar, the 1582 Gregorian reform actually removed February 29th from three in every 400 years. In the Gregorian calendar, any century year which is not divisible by 400 will not be a leap year and will not have a February 29th. This will next happen in the year 2100.

Should Patsy choose to delve into The Irish Times archives, he would find that your edition of Wednesday, February 28th, 1900, was followed by that of Thursday, March 1st; there was no February 29th in the year 1900.

Patsy’s predecessor in 1900 could have credited the absence of a February 29th in that year to Gregory XIII while credit for every leap-year day in the past 2,000 years can be laid at the door of Julius Caesar. – Yours, etc,