Commissioned for the sesquicentennial of Gettysburg College, Sentinel is Puryear’s first work in masonry. Puryear chose to work with fieldstone after viewing many houses and barns in Gettysburg, Pennsylvania, made of this material. In so doing, he paired a traditional, local process with an abstract, contemporary sculpture—a notable approach in a town that is home to many traditional bronze monuments to the Civil War. Describing this process, Puryear has recalled that he used "the fieldstone and mortar that had been used in barns and houses in that area of Pennsylvania by the German settlers for centuries—but to use those materials to make something that’s very clearly mine.”

To make the work, Puryear crafted a latticed wooden mold at his Chicago studio and transported it to the site. There, he worked with a recent graduate from Gettysburg’s art program, Nick Micros, to lay fieldstone into the mold. Fieldstone was plentiful on campus, making it possible for Puryear to source materials for the work from areas of the college that were under construction. After the sculpture was completed, the hollow center was filled with cement. The maquette on view here, however, is created from wood that Puryear carved by hand and painted to resemble stones and mortar.