St. Mary’s School for Boys opened on July 1, 1850. At the time, Dayton had a population of 10,977. One of the first year’s 14 students was Laurence Butz, who later became mayor of Dayton.

The fact that the drop coincided with the university’s decreasing enrollment was not a coincidence, a Moody’s official said then, and news about the sale of the artwork also was a factor that ...