Historic Wetherill Mansion in Philadelphia's Rittenhouse Square damaged by fire

PHILADELPHIA (WPVI) -- A fire erupted at a historic building in Rittenhouse Square early Friday morning.

Flames were reported at the Wetherill Mansion building around 4:30 a.m.

Video from Chopper 6 showed heavy damage to the roof of the building.

One firefighter was taken to the hospital to be treated for heat exhaustion.

The blaze was contained to the roof of the unoccupied building.

There was no immediate word on the cause of the fire.

The building was built in 1906 and was the longtime headquarters for the Philadelphia Art Alliance. It was recently purchased by the Curtis Institute of Music.