In 1917, just as the United States joined the Allies and declared war against Germany, the city of Wilmington was in an uproar over the pro-German political activities of a local pastor, Sigmune George Von Bosse. Von Bosse ran a German School on Sixth and Jackson Streets attended by Thomas Herlihy, Jr., the son of an Irish father and a German-born mother. Herlihy recalled that in the early 1900s, Wilmington was home to German cultural societies such as Deutsch House, Turners and a Saengerbund, and at least three German churches representing Lutherans, Catholics and Baptists. Judge Herlihy laments the loss of community in Wilmington

Herlihy pointed to the "Van Bosse Affair" as the beginning of the decline of a strong German cultural identify and community in Wilmington. While most Germans felt strong ties to their homeland, they did not support the fatherland's political or military activities. Pastor Von Bosse's efforts to rally the community to raise funds for the German war failed when the "old-line Germans stood up against him and denounced him." Von Bosse fled to Mexico and returned to Germany. In Wilmington, the churches discontinued services in German and the Baptist church folded. The Oktoberfest at Brandywine Springs was no longer held. "The disintegration of the German community as such [followed] this incident that occurred with Von Bosse," Herlihy said.
In 1979, an organization called the Delaware Saengerbund revitalized interest in German culture and traditions by sponsoring an annual Munich-style Oktoberfest, still held each September in Newark.