Ireland's 1948 Grand Slam captain Dr Karl Mullen has died at the age of 82.
His passing comes barely a month after Ireland won the RBS 6 Nations Championship and secured their first tournament clean sweep since that 1948 season.
Irish Rugby Union president John Lyons said: "I would like to express my personal sorrow and that of the Irish Rugby Football Union on the sad passing of Karl Mullen.
"He was one of the great heroes of Irish rugby, and leaves a lasting legacy for his contributions as a renowned hooker for Old Belvedere, Leinster, Ireland and the Lions, and also for his input after his distinguished playing days as a committed and enthusiastic administrator of the game.
"I had the privilege of playing for Bective Rangers against Karl, and I witnessed at first hand his great leadership and skills on the rugby field. I extend the sympathies of Irish rugby to his family."
Educated at Belvedere College and Royal College of Surgeons, he went on to play for Old Belvedere RFC and gained the first of his 25 Ireland caps in 1947 against France.
Mullen led Ireland to a second successive Triple Crown in 1949 following the previous season's Grand Slam glory, and a year later he was chosen as captain for the British and Irish Lions' tour to Australia and New Zealand.
He played in 17 games on the tour, including three Test matches, while his career as a rugby administrator included a spell as chairman of the Irish selectors and Leinster president in 1963/64.
And he was able to look on earlier this year as Ireland ended a 61-year wait for the Grand Slam when they beat Wales in Cardiff, landing the Six Nations title following earlier victories over France, Italy, England and Scotland.