Gérard Houllier, the French football manager who won multiple titles coaching Premier League's Liverpool and Ligue 1's Olympique Lyonnais, died at the age of 73 on Monday.

Houllier suffered from heart problems for a long time. In 2001, he was rushed to hospital at the half-time of a game between Liverpool and Leeds United.

One highlight of Houllier's 38-year-long coaching career largely was at Anfield between 1998 and 2004. In the 2000-01 season, he led Liverpool to win five titles of the UEFA Cup (today's UEFA Europa League), the UEFA Super Cup, the FA Cup, the Football League Cup and the FA Charity Shield.

"We are mourning the passing of our treble-winning manager, Gerard Houllier. The thoughts of everyone at Liverpool Football Club are with Gerard's family and many friends. Rest in peace, Gerard Houllier 1947-2020," posted Liverpool on Twitter.

"Absolutely heartbroken to hear that my old boss, Gérard Houllier, has sadly passed away. A great manager and a genuinely caring man. #RIPBoss," tweeted Michael Owen who played for the Reds between 1996 and 2004.

After Houllier left Anfield in May 2004, he returned home and joined Lyon which were still dominating the French top league at the time. He brought the Ligue 1 trophy to the Stade de Gerland twice accompanied by two Trophée des Champions titles.

"With the death of Gérard Houllier, the football world has lost a legend and Olympique Lyonnais has lost a friend. Gérard will be missed terribly. All of our thoughts are with his family," the French club wrote on Twitter.

The last club Houllier coached was Aston Villa. He succeeded caretaker Kevin MacDonald in early September 2010 and was replaced by another caretaker Gary McAllister in late April 2011. Although that coaching period was neither long nor successful, Villa Park still paid respect to Houllier.

"All at Aston Villa are deeply saddened to learn of the passing of Gérard Houllier, our manager during the 2010/11 season. Our thoughts are with Gérard's loved ones at this incredibly difficult time."

Houllier also coached the French national team for less than a year after working as assistant manager for four years. However, he failed to keep the manager job after France failed to make the FIFA World Cup in the United States.

Houllier was the fifth football legend the sport has lost in about 20 days following Diego Maradona, Papa Bouba Diop, Alejandro Sabella and Paolo Rossi.