St Mary & St Mercurius Coptic Orthodox Church of Greater Philadelpiha, which makes its home in the former SS. Cosmas & Damian Church in Conshohocken, recently hosted a performance of the David Ensemble. The ensemble performs Coptic hymns that have been preserved for over 2000 years through an oral tradition. You can read about the history of the hymns here.
Below are two videos of the performance: