In the process of hiring a new head coach, San Francisco 49ers CEO Jed York twice brought up the name of Bill Belichick. Not as a candidate, of course, but as a guideline.

For York, Belichick's New England Patriots brought to mind a couple of admirable tenets: having a head coach who is constantly teaching players on both sides of the ball and having a system in which assistant coaches are developed and promoted from within, much like the days of Bill Walsh, George Seifert and their teams of the 1980s and 90s.

With that, Monday's hiring of Eric Mangini as the 49ers defensive coordinator should come as no surprise.

Mangini, or "Mangenius" as he was called in New England, got his first NFL job under Belichick and with the Cleveland Browns in 1995. Five years later, after stints under Ted Marchiboda (Baltimore Ravens) and Bill Parcells (New York Jets), Mangini rejoined Belichick as the Patriots defensive backs coach.

By 2005, a decade after the two men first worked together, Mangini was Belichick's defensive play-caller. (They won three Super Bowls in six seasons together.)

And although Mangini, 44, has spent the bulk of his coaching career on that side of the ball, he spent the last two seasons coaching the 49ers offense -- a veteran coach developing himself for future promotion.

In other words, to borrow general manager Trent Baalke's phrasing, Mangini "checked off a lot of boxes."

He'll now be charged with coordinating and calling the plays for a defense that his predecessor, Vic Fangio, led to top-of-the-league rankings in each of the past four seasons.

He'll also be side by side with first-time head coach Jim Tomsula, who should benefit from Mangini's own experience as the leading man.

Like Tony Sparano, who will take over Mangini's role as San Francisco's tight ends coach, Mangini was previously a head coach for two NFL teams: the New York Jets (2006-08) and the Browns (2009-10).

There are also former NFL coordinators among Mangini's defensive assistants: Raiders coordinator-turned-49ers senior defensive assistant/linebackers coach Jason Tarver as well as new inside linebackers coach Clancy Pedergast, who previously led the defense of the Arizona Cardinals (2004-08) and the Kansas City Chiefs ('09).

Will the group employ a 3-4 alignment on defense? Will they blitz more or less often than in the past? What is their philosophy?

We'll have answers to those questions in the coming days.

For now, here are a handful of other notes on the new DC:

• He is a native of Hartford, Conn.
• He holds Wesleyan University's single-season (11.5) and career (36.5) sacks records.
• He joined the Chi Psi fraternity that Belichick had been a part of years earlier.
• He coached an Australian semi-pro football team to two regional titles while he was an upperclassmen.
• He graduated with a degree in political science.
• He was a ball boy for Belichick and the Browns before moving into coaching.
• He now has 18 years of NFL coaching experience.
• He appeared in a cameo on the "The Sopranos" while he was head coach of the Jets.
• He was the league's youngest leading man, at 35, when hired by New York.
• He took a break from coaching in 2011, working as an ESPN analyst.
• He has three sons, and they take their middle names from men in football that have influenced Mangini: Brett Favre, Rodney Harrison and, of course, Belichick.