"The music is by Reinhard Keiser who was a German composer of the generation immediately before George Frideric Handel," says Stone.
"We really go looking for things that are discoveries," says Roberts. "It's not your grandma's Baroque music."
In this concert, they're telling the story of Handel's cheating ways.
"He pinched Keiser's stuff," says Stone.
As the story goes, Handel worked for Keiser but was more successful than his boss. When Keiser got jealous, Handel quit.
"But when he quit, he took with him five years' worth of Keiser's music in a suitcase, and used that music throughout his lifetime," says Stone.
"Literally stolen" says Roberts.
The drama plays out in four works, two concertos and two suites.
"One is by Keiser from his opera Hercules, which was in the package that Handel stole," says Stone. "Then we do the Terpsichore, Pastore Fido suite of Handel, which also has borrowings."
Baroque music has no conductor.
"It's really interactive and collaborative," says Roberts.
Stone says audiences will see a lot of communication "between the artists on the stage."
"We play on mostly copies of historical instruments from the 18th century," says Roberts. "My flute is made of wood and has just one key on it."
"We like to say that we play the best Baroque music you've never heard," says Stone.
"And once you hear it, you'll never go back," says Roberts.
Tempesta di Mare, Philadelphia Baroque Orchestra presents Stolen October 5 in Center City and October 6 in Chestnut Hill.
Tempesta di Mare, Philadelphia Baroque Orchestra | Stolen
Saturday, Oct. 5 at 7:30 p.m. at Trinity Center for Urban Life | Tickets
Sunday, Oct. 6 at 4 p.m. at Presbyterian Church of Chestnut Hill | Tickets