The first building erected after purchase of the campus in 1856 was Clet Hall. It was built in 1862 to house Our Lady of Angels Seminary, the institution that was the forerunner of Niagara University.
The complex now serves as a residence hall and also houses the dining halls, the campus club, the Leary Theatre, and the theater department offices.
Clet is named for Francis Regis Clet, a Frenchman who served as a Vincentian missionary in China for the last 30 years of his life (1748-1820). He was martyred by strangulation during an anti-Christian persecution and beatified in 1900.