It was the impregnable fortress of heritage labels. Behind its clapboard walls lay an unlikely grail. Let international designers like Junya Watanabe and Demna Gvasalia have their way with Red Wing, Filson and North Face. Nobody touches L.L. Bean.

Until this week, that is. Though scores of others had tried without success to breach the resistance of a staid and privately owned Yankee institution, in the end what worked for the Midwest-born designer Todd Snyder was, he said, a healthy dose of “Iowa nice.’’

Thus, for the first time in its 108-year history, L.L. Bean will appear on a runway, as a core element of Todd Snyder’s fall men’s wear show, the tent pole event of New York Fashion Week: Men’s.