The mother of rock 'n' roll is being honored in Philadelphia almost 40 years after her death.

Sister Rosetta Tharpe was a gospel singer with an electric guitar who crossed over into popular music in the 1940s and '50s.

Outside a modest row home at 11th and Master streets, the state of Pennsylvania has erected an historic marker honoring Tharpe at the site of her final home.

She was a lady with a big voice and a flashy stage presence who made gospel music beg, scream, and shout.

"She was revolutionary in being the first crossover artist," said Karen Galle of the Pennsylvania Historical and Museum Commission. "She introduced elements of secular music and really popularized gospel music."

She also tore up her guitar. She was like Chuck Berry, but twice his size, 10 years older, and a lady who never left the church.

The request for the marker came from a group called the Friends of Sister Rosetta Tharpe and Girls Rock Philly, a summer rock 'n' roll camp. Even to 13-year-old campers, Tharpe is cool.

"We do show video in a lot of our workshops," said camp director Beth Warshaw-Duncan. "So when you see her play guitar, the girls get really excited about the picking she is able to do."

Due to recent state budget cuts, the Historical and Museum Commission no longer pays for any portion of the historic markers it erects. All costs were paid by the people who nominated Tharpe for consideration.

It took three years to raise $1,400, but Warshaw-Duncan says she is thrilled to be part of the effort honoring a guitar hero.