[2] It was founded as a volunteer private military company at a time when the common or constitutional militia[3] languished due to uninterest and neglect by state politicians.

At the time of its founding, the unit was called The Cleveland City Guards but within the next year the membership decided that their organization would be known by reference to the gray color of their uniforms.

[2] Reforms of the country's militia system which began with the Militia Act of 1903 and continued with subsequent legislation at the state and federal levels meant that the era of private military companies' official participation in national military affairs had come to an end and while the Grays, under the leadership of Ludwig S. Connelly, were able to enlist in the Ohio National Guard (ONG) for duty during the Mexican Punitive Expedition, they essentially did so as a group of private citizens enlisting en masse and not as a private military company.

Their participation in World War I, which began immediately upon their ONG unit's release from duty on the Mexican border, was the last conflict in which the Grays saw active service even as a group of enlistees.

Until construction was completed in 1893, the company found a temporary home at the Gatling Gun Battery Armory on Sibley Street.

The tower has '3 x 5' foundation blocks, the main entrance corners and the front window lintels are all of solid rough-hewn sandstone.

This building was originally built to house weapons and provides a drill hall for the militia; this edifice quickly evolved into a vital community center for the turn-of-the-century Clevelanders.

Beyond stewardship of the building and conservation of artifacts, the museum strives to preserve the traditions and the rich heritage of those who serve their country and their community.

The museum actively fulfills this objective by preserving, interpreting and presenting the military history of the United States.