GLEN ARBOR, Mich. (AP) — William Post, a Michigan man who played an important role in the development of Pop-Tarts, has died at age 96.

Post died Saturday, according to a family obituary which provided no details on his death but says he was raised in Grand Rapids as “one of seven children of Dutch immigrants” and had retired at age 56 as a senior vice president with Keebler Company and settled in Glen Arbor, Michigan.

Kellanova, formerly known as Kellogg Co., said in a statement Wednesday that it was “deeply saddened” by Post’s death.

“He played an important role in co-creating the iconic Pop-Tarts brand and we are grateful to Bill for his legacy and lasting contributions to our company,” Kellanova said without elaborating.

Pop-Tarts debuted in 1964 in Cleveland, Ohio. The toaster pastry was originally sold in four flavors — strawberry, blueberry, brown sugar cinnamon and apple-currant — before it was released nationwide the following year, Kellanova’s website states.

Post’s family wrote in his obituary that he was a plant manager with a company later known as the Keebler Company when Kellogg executives asked him “if he thought it would be possible for Keebler to create a new product they had in mind.”

His obituary states that one of the executives was Kellogg chairman William LaMothe, who “soon became Bill’s close friend.”

“It is at this juncture that Bill is often credited for having ‘invented’ the Pop Tart. To be accurate, however, Bill would say, ‘I assembled an amazing team that developed Kellogg’s concept of a shelf-stable toaster pastry into a fine product that we could bring to market in the span of just four months,’” according to the the obituary.

Post, whose wife, Florence, died in 2020, is survived by a son and daughter and several grandchildren and great-grandchildren. A service for Post will be held March 7 at Christian Reformed Church in Grand Rapids, according to his obituary on the Matthysse Kuiper DeGraaf Funeral Home’s website.