Named Musical America's "Ensemble of the Year" for 2004, San Francisco's Philharmonia Baroque Orchestra has dedicated itself to the historically-informed performance of Baroque, Classical, and early Romantic music on original instruments since its inception in 1981. Under the leadership of Nicholas McGegan, Music Director since 1985, Philharmonia has become "an ensemble for early music as fine as any in the world today," according to Los Angeles Times critic Alan Rich. The Orchestra performs a subscription season in four cities in the San Francisco Bay Area, and is regularly heard on tour in United States and internationally. In addition to Mr. McGegan, the Orchestra has welcomed eminent guest conductors to its podium including William Christie, Andrew Parrott, Jordi Savall, Gustav Leonhart, Monica Huggett and Stanley Ritchie.

Under the direction of Mr. McGegan, Philharmonia has made several United States tours, each of which included an appearance on the Great Performers Series at Lincoln Center. Other appearances include debuts at Carnegie Hall (NY) and Walt Disney Concert Hall (Los Angeles) in February 2005. In August of 2005 the Orchestra made its debut at the BBC Proms, Snape Maltings (UK) and The Concertgebouw in Amsterdam.

In August 2002, the Orchestra made its Mostly Mozart Festival debut with five performances including a concert featuring Handel's newly-discovered Gloria in excelsis Deo and four performances of Handel's L'Allegro, il Penseroso ed il Moderato with Mark Morris Dance Group. A return engagement in August 2003 featured the Orchestra in the Festival's first fully-staged opera, Mozart's Il re pastore. In March of 1998 Philharmonia performed Handel's Saul and Hercules at the Brooklyn Academy of Music, and in 1999 the Orchestra made its European debut at the International Handel Festival in Gottingen, Germany, with return appearances in 2001 and 2002.