Bill Belichick is the only head coach in NFL history to win three Super Bowl titles in a four-year span. He spent 20 years as an assistant coach in the NFL and this is his 15th season as a head coach. According to the Elias Sports Bureau, he is the only man in NFL history to serve 20 or more seasons as an assistant coach and at least 15 seasons as a head coach. Over a 100-game span from 2003-08, Belichick directed the team to an 82-18 record, marking the best 100-game span for any team in NFL history. In the 2007 season, Belichick led the Patriots to the fourth undefeated and untied regular season in the NFL's 88-year history and the first since the NFL established a 16-game schedule in 1978. He has led the Patriots to the Super Bowl four times in the last eight seasons and has produced seven division championships in the last nine seasons, including five straight from 2003-07. Belichick's Patriots teams own the all-time NFL records for consecutive total victories (21 from 2003-04), and established the record for consecutive regular-season victories (21 from 2006-08) and consecutive playoff victories (10 from 2001-05). Belichick owns the second-best postseason record in NFL history (15-5) and is the winningest NFL head coach since 2001 (121-41). From 2003-04, he directed the Patriots to back-to- back Super Bowl titles while posting consecutive 17-win campaigns. Belichick has spent more seasons in the league than any other current NFL head coach, and in that time has been a part of five Super Bowl championship teams. His overall record of 126-52 with the Patriots gives him the most victories and the best winning percentage of any head coach in franchise history.