In 1860, Bishop Michael Flannery launched a plan to upgrade Nenagh Castle, a fine specimen of Norman architecture located on the patch of land he’d just purchased in Tipperary, Northern Ireland. For funding, he relied on donors from North America, among other sources. Naturally, when the U.S. Civil War broke out in 1861, the flow of funds dried up, and the bishop was forced to halt construction. Flannery did manage to leave his mark on the castle in the form of a series of battlements with windows. Little did the bishop know his crowning legacy would help solve a surveyor’s dilemma one-and-ahalf centuries later.