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When did Johnny Unitas start playing with the Baltimore Colts
In 1956, Johnny Unitas joined the Baltimore Colts.
What position did Johnny Unitas play for the Baltimore Colts?
Johnny Unitas was a quarterback.
How did the 1956 season fare for Johnny Unitas playing for the Baltimore Colts?
Johnny Unitas threw nine touchdown passes that year, including one in the season finale that started his record 47-game streak. His 55.6-percent completion mark was a rookie record.
How did Johnny Unitas do the following 1957 season?
In 1957, Johnny Unitas's first season as the Colts full-time starter at quarterback, Unitas finished first in the NFL in passing yards and touchdown passes.
What else happened with Johnny Unitas in the following 1957 season besides being first in the NFL in passing yards?
At season's end, Johnny Unitas received the Jim Thorpe Trophy as the NFL's Most Valuable Player by the Newspaper Enterprise Association.
What happened in the following 1958 NFL season with Johnny Unitas?
Johnny Unitas continued his prowess in 1958 passing for 2,007 yards and 19 touchdowns as the Colts won the Western Conference title.
What else is of note about the Johnny Unitas's Colts in the 1958 season?
The Colts won the NFL championship under Johnny Unitas's leadership on December 28, 1958, by defeating the New York Giants 23–17.
Did Johnny Unitas receive any other awards besides the NFL championship around this time?
In 1959, Johnny Unitas was named the NFL's MVP by the Associated Press for the first time, as well as United Press International's player of the year.

Question: When did he leave the Colts?
Self-contained rewrite: When did Johnny Unitas leave the Boltimore Colts?