Writing in The Guardian, Ian Malin argues that while 'Alfie' was the first Welshman to win 100 caps, he will remembered best for his announcement in 2009 that he is gay.
"In his final game for Wales, Gareth Thomas became their first rugby union international to reach 100 caps, an epic World Cup match against Fiji in Nantes during 2007. But it was his decision some two years later to announce to the world he is gay, so breaking a taboo in a macho sport, that brought him to the attention of the wider world.
"Thomas said back in 2009 that he did not want to be known as a gay rugby player. 'I am a rugby player and first and foremost I am a man,' he said. In the event that decision hardly caused a stir in South Wales, where his sexuality was an open secret, and the international referee Nigel Owens had also come out, but it was a pretty brave decision at the time and one of many incidents in one of Welsh rugby's most colourful life stories.
"Thomas on Tuesday made another announcement - that he is leaving rugby for good. It was less earth-shattering, given that he is now 37 years old and his rugby league club, the Crusaders, are no longer a Super League club. But he had been expected to join Wigan next season and, in the shorter term, play for Wales in theforthcoming Four Nations tournament, starting against England this weekend. Thomas, who has returned home after a stint as an ITV analyst during the rugby union World Cup, had met up with his new Wales team-mates and left them perplexed by telling them he will not be available for the tournament for "personal reasons."