Service in the army
The man hoped to propose to his would-be wife prior to World War II. Unfortunately, he didn't have the money to purchase a ring. Three years later, he managed to purchase a ring while stationed in London. He fought his way across France and into Berlin, keeping the rings around his dog tags. When he returned home, he proposed at the Brooklyn Navy Yards.
The ring he used to engaged was passed down and used for future generations of the Allen family. After Nora Allen's death, the ring was held by Joe who passed it on to Barry Allen to propose to Iris West.