Jonathan Casillas grew up in New Jersey, right in the heart of Giants territory. And he played for seven NFL seasons and won two Super Bowls before he signed with the Giants in 2015.

Yet even he did not appreciate the full scope of what it means to play defense for this franchise until he arrived with the team.

“I had a feeling,” Casillas said on Sunday. “I remember LT [Lawrence Taylor] when I was young. I remember Jessie Armstead when I was young. But I don’t remember everybody. All the guys, the Harry Carsons, the George Martins, I didn’t know those guys, per se, and the impact they’ve had and how strong the Giants defense has been for decades.”

Which is why Casillas and others are willing to excuse the younger players from other parts of the country who may be in the same situation, unaware of their link to the ghosts of Giants defenses of the past.

“I don’t know if they can grasp that yet,” Casillas said. “And I think it’s our job and the coaches’ job to not only show them the history, but establishing them in what we have going on right now.”

The Giants tried to infuse the players last season with that sense of history. Defensive coordinator Steve Spagnuolo would have the players research former greats and present their reports to the rest of the group. It was a way of reminding them of their place in the culture.

This year Casillas is continuing that education whenever he can. He doesn’t have to look far, either. The Giants have Armstead and Antonio Pierce on the field with them this summer. Armstead is the team’s special assistant to player development, Pierce is a coaching intern.

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The Giants’ biggest cultural stars often have been offensive players, from Frank Gifford to Odell Beckham Jr. But their championship teams always have been rooted in defense and any rank of their greatest all-time players will tilt heavily toward that side of the ball.

Can the present group accomplish what those of the past did? They made tremendous strides last year, jumping from the worst defense in the league to one of the best.

“I think we can be as good as we want to be,” Casillas said. “It’s a new year. Similar guys, but not the same. We lost a big piece in [defensive tackle Johnathan] Hankins and we’ve got to have a guy step up with him gone. We’ve got to play really solid on the back end. Our linebackers have to really step up this year and play, if not better, but bigger than we’ve ever played since I’ve been here. That’s just to keep account with all the guys on the front end. You’ve got JPP [defensive end Jason Pierre-Paul], OV [defensive end Olivier Vernon] and ‘Snacks’ [defensive tackle Damon Harrison]. Those guys are feared around the league and we’re just trying to play up to their tempo.”

And make a little history of their own.