Sotheby’s will offer some 50 works from the collection of Seattle real estate developer Richard “Dick” Hedreen this fall and winter, in a series of sales expected to bring at least $90 million.

The sale comes two years after Hedreen pledged his and his late wife Betty’s collection to Seattle University, along with $25 million in seed money to establish a new art museum there. Rather than a reversal of that gift, the family says the sale is intended to help make it happen.

Around 350 works are earmarked for the university, including paintings by Willem de Kooning, Rashid Johnson, Amy Sherald, Cecily Brown, and Jonas Wood, as well as Old Masters works by Bronzino, Jacopo Pontormo, Élisabeth Vigée Le Brun, and Thomas Gainsborough.