Mantua Seminary, a coeducational institution sponsored by the Mantua Masonic Lodge, was located in Mantua, sixteen miles north of McKinney in Collin County. Both the school and the town were projects conceived by William C. McKinney, James W. Throckmorton, and Joseph Wilcox. In 1854 the three McKinney residents purchased 200 acres of land from Younger Scott McKinney, son of Collin McKinney. The land was divided into town lots and sold, and part of the profit was set aside to finance the school. Although chartered on September 1, 1856, the seminary did not offer classes until 1859. Because of the failure to collect enough money to construct a school building and the outbreak of the Civil War, classes originally were held on the first floor of the Mantua Masonic Lodge building. In 1865 a two-story, sixteen-room building was constructed.
The seminary operated successfully for the first decade following the war. Classes were generally of high-school level and were taught by a faculty that at one time numbered eight. In 1868 eighty students enrolled in the school, paying tuition that ranged from ten to twenty dollars. Four years later, however, most of the residents and businesses of Mantua moved to the new town of Van Alstyne, built on the Houston and Texas Central Railway line in southern Grayson County. The seminary continued to offer classes in the nearly deserted Mantua until the early 1880s, when it ceased operation.