Joseph Sylvio Theobald Mantha - Born April 14, 1902 in Montreal, Quebec – Died August 7, 1974 in Montreal, Quebec was a Canadian Ice Hockey defenceman and coach.

Born and bred in the St. Henri district of Montreal, Mantha first made a name for himself as a right wing with the Notre Dame de Grace juniors in 1918-19. That was followed by apprenticeships with Verdun in the Intermediate Mount Royal Hockey League, Montreal Imperial Tobacco and Montreal Northern Electric in the city's industrial league and a short stint with the Montreal Nationale of the Quebec senior amateur league. Well-known coach Arthur Therrien made an indelible impression on Mantha while coaching him at Verdun.

Mantha's four goals in nine games with the Nationale attracted the attention of Montreal Canadiens General Manager Léo Dandurand, who signed him and had Mantha in uniform to start the 1923-24 NHL season.

The Canadiens started Mantha as a forward, then moved him to right defence, because veterans Sprague Cleghorn and Billy Coutu were aging, which turned out a smart decision, as Mantha would establish the standard of excellence for stay-at-home defensemen for generations to come.

Mantha only had 1 goal, 3 assists in his NHL rookie season, but he was a tough, strong and mobile defenseman, that opposing forwards had no easy way to get around. Montreal would win the 1924 O'Brien Trophy as NHL playoff champions, and the 1924 Stanley Cup championship in his first NHL season.

When Cleghorn was traded just before the 1925–26 NHL season, Mantha gained a more prominent role on the Canadiens. Mantha would also have the first penalty at the new Madison Square Garden - a first-period minor for holding Billy Burch of the New York Americans on December 15, 1925. The evening marked a debut, too, for the new Prince of Wales Trophy, which Montreal took home along with their victory, with New York’s incoming mayor, Jimmy Walker, presenting the cup to Montreal captain Billy Coutu at the game’s conclusion. Canadiens would hold it only until the end of the season, when it went to the team that won the NHL championship. In 1926, that happened to be Montreal’s other team, the Maroons.

Mantha's tireless efforts and dedication to the Canadiens success led to Mantha’s appointment as team captain to start the 1926-27 season. This was a title that, with the exception of one year, he would proudly hold for the rest of his playing career in Montreal. Mantha scored 10 goals, 5 assists in his first year as captain.

In the 1927-28 season, Mantha helped the Canadiens win the 1928 O'Brien Trophy as NHL Canadian Division champions.

In the 1928-29 season, Sylvio had his younger brother Georges join the Canadiens, and Montreal iced one of the NHL’s first and most talented brother acts. They played together for the next eight years.
Mantha also scored the first-ever goal in Boston Garden on November 20, 1928, leading the Canadiens to a 1–0 win over the Boston Bruins. the Canadiens would go on to win the 1929 O'Brien Trophy as NHL Canadian Division champions.

In the 1929-30 season, Mantha had a career year, scoring 13 goals, 11 assists and a whopping 108 penalty minutes. In the 1930 playoffs, Montreal defeated the Chicago Black Hawks and the New York Rangers to reach the Stanley Cup final, where they would play the heavy favourites, Boston Bruins, who had lost only 5 games all season, including defeating the Canadiens in their 4 games earlier in the season. Montreal would win the 1930 Stanley Cup championship, defeating the Bruins in 2 straight games. Mantha had 1 goal in the first game, and another goal in the second game, but only had 1 penalty in the series, a roughing call in the 3rd period of game 2.

Montreal had another strong season the next year, winning the 1931 O'Brien Trophy as NHL Canadian Division champions, then defeated the Bruins in the Stanley Cup semi-final. The Canadiens would play the Chicago Black Hawks for the championship. Mantha again scored in the first game, and 1 goal in the third game. The series went 5 games, with Wildor Larochelle getting the overtime 1931 Stanley Cup winning goal for Montreal. It should be noted that Mantha's brother Georges, had the winning goal in both the second & third games of the series.

Sylvio Mantha was named to the NHL Second All-Star Team in both the 1929–30 and 1930–31 seasons.

Montreal would win the 1932 O'Brien Trophy as NHL Canadian Division champions, but would lose to the New York Rangers in the Stanley Cup semi-final.

In the 1935–36 NHL season, Mantha became the Canadiens' player coach. After a dismal season, the Canadiens fired him. The Boston Bruins were involved in a contract dispute with Eddie Shore so they signed Mantha at the start of the 1936–37 NHL season—and gave him Shore's number 2 jersey. Four games into the season, Mantha admitted he could no longer play at a competitive level and retired.

Mantha appeared in 538 regular season games, scoring 63 goals, 78 assists, and 5 goals, 5 assists in 47 playoff games. His 737 penalty minutes secured his spot as one NHL’s best tough guys in the league’s early days.

After retiring, Mantha tried his hand as a linesman and referee in the American Hockey League and the NHL. However, the grueling travel schedule of an on-ice official proved to be too much.

Mantha decided to stay in Montreal and ply his trade as an amateur coach. He coached the Montreal Concordias until 1943, when he switched to the junior ranks. Mantha passed his wealth of experience on to young players on the Laval Nationales from 1943 to 1945, the Verdun Maple Leafs from 1945 to 1947 and the St. Jerome Eagles from 1947 to 1948.

Sylvio Mantha was inducted into the Hockey Hall of Fame in 1960.

The Georges and Sylvio Mantha Arenas are part of the Complexe Récréatif Gadbois in Montreal and named for him and his brother, Georges Mantha.