On October 10th 2009, at the beginning of last season, Brett Favre turned 40 years old.
He went on to have arguably his best season ever.
So where does he fit in among all-time 40-year-old quarterbacks?
There have been 17 different NFL quarterbacks to see playing time after their 40th birthday.
Let's countdown the top five 40-year-old quarterbacks of all time.
Len Dawson is a Hall of Famer who is known most for his years with the Kansas City Chiefs.
His career started when he was 21 and spanned 19 seasons.
He turned forty during his final year with the Chiefs.
In that season he played in 12 games, starting five of them.
He finished the year with five touchdowns, four interceptions, a 66.4 percent completion percentage, and a 90.0 quarterback rating.
Doug Flutie played 12 seasons in the NFL (with an eight-year gap in the middle) for four different teams.
Flutie played 15 games over four years after turning 40. He played until he was 43.
At the age of 41, Flutie started five games for the San Diego Chargers, winning two of the games.
He finished that season with nine touchdowns, four interceptions and an 82.8 quarterback rating.
Sonny Jurgensen played 18 consecutive seasons in the NFL, most notable for the Washington Redskins.
Sonny turned forty during his final year in the league.
That season he played in 14 games, starting four of them and earning a record of 3-1.
He finished the year with 11 touchdowns, five interceptions, a 64.1 completion percentage and a 94.5 quarterback rating.
Vinny Testaverde played 21 seasons in the NFL all the way up until after his 44th birthday.
He played in an impressive 39 games after turning 40, starting 32 of them.
His record as a starting quarterback over 40 is 10-22.
In 2004 he started all but one game for the Dallas Cowboys.
He finished the year with 17 touchdowns, 20 interceptions, a 60.0 completion percentage and a 76.4 quarterback rating.
Warren Moon is a Hall of Famer who played 19 seasons in the NFL.
He played in 36 games after turning 40 and started all but 3 of them.
During that stretch he compiled a starting record of 15-18.
His best year as a 40-year-old came in 1997 with the Seattle Seahawks,
He finished the season with 25 touchdowns, 16 interceptions, 59.3 completion percentage and an 83.7 quarterback rating.
Brett Favre is easily the best 40-year-old quarterback the NFL has ever seen.
In his 19th season in the league he had arguably his best year yet.
Last season with the Minnesota Vikings, at the age of 40, Brett Favre threw 33 touchdowns and 7 interceptions.
He had a completion percentage of 68.4 and a quarterback rating of 107.2.
He led the Vikings to a 12-4 record and the NFC Conference Championship.
He has started in 285 consecutive games dating back to 1992 and looks to continue that streak this season at the age of 41.