Football has been left shocked by the sad news of Gerard Houllier's passing at the age of 73."We are mourning the passing of our treble-winning manager, Gerard Houllier," a Liverpool statement read."The thoughts of everyone at Liverpool Football Club are with Gerard's family and many friends."Houllier also managed Lyon, PSG and the French national team. His final job was with Aston Villa, whom he left in 2011 after nine months due to heart problems.Tributes have been flooding in for a boss who not only won 12 honours over the course of a distinguished career, but was also described as warm, generous and exceptionally supportive to his players.The Frenchman is perhaps best known in English football for helping Liverpool to their cup treble in 2001, helping them to the UEFA Cup, League Cup and FA Cup. He also played a significant role in the development of a number of greats, including Steven Gerrard and Jamie Carragher.Michael Owen, who won the Ballon d'Or while playing under Houllier at Anfield, took to Twitter to pay his respects."Absolutely heartbroken to hear that my old boss, Gérard Houllier, has sadly passed away," Owen wrote.

"A great manager and a genuinely caring man. RIP Boss."

Carragher also updated his profile picture to an image of his former manager and echoed those thoughts upon hearing the sad news.

"Absolutely devastated by the news about Gerard Houllier, I was in touch with him only last month to arrange him coming to Liverpool. Loved that man to bits, he changed me as a person & as a player & got @LFC back winning trophies. RIP Boss."

Our thoughts and prayers are with all Houllier's family and many friends at this difficult time.