Six or seven of horses from the Division Cavalry Brigade barn in north St. Louis County wandered the campus of Larimore Elementary School Tuesday, causing officials to keep children and staff inside for about an hour.

The St. Louis Post-Dispatch reports the 14 horses of the Division Cavalry Brigade are used to teach Civil War history and serve children and veterans with special needs. Their owner, Terry Crowder, says the horses had visited the school before.

Police were able to coax the horses back to their home, which is about 300 yards from the school.

Crowder believes someone accidentally left a gate to a pasture open.