Thirty-three years, or a third of a century, is a long time in any organization’s history. In her pre-concert remarks, Princeton Pro Musica Artistic Director Frances Fowler Slade commented that when she first wanted to start a chorus in Princeton she was told that “the last thing Princeton needed was another music ensemble.” On the contrary, in the past thirty years, the Princeton area has exploded with high-quality musical performances, and Princeton Pro Musica has grown right along with the musical community. After thirty-three years, Ms. Slade has decided to pass on the Pro Musica baton to a new choral visionary, and the chorus honored its founder on Sunday afternoon with a final performance under Ms. Slade’s direction. Choosing what could be the most towering choral work going, Ms. Slade, chorus, soloists and orchestra brought J.S. Bach’s Mass in B minor to spirited life in Richardson Auditorium.

It surely was not easy to conduct the last concert of an ensemble that she has brought up like a child, but Ms. Slade was all business when it came to Bach’s intricate music. Tempi were quick with instrumental soloists finding nuance within the speed, and the chorus showed off three decades of choral discipline in its handling of coloratura runs. Movements which often get bogged down in over-romanticization moved right along, with the pathos and poignancy of the Biblical text conveyed by Baroque phrasing and tapered cadences.

Bach probably never heard all the components of this monumental work performed together as a single unit in his lifetime, but since the 19th-century revival of interest in Bach’s music and evolution of the choral society it has become a staple of choral performance, featuring up to five choral parts and four soloists, accompanied by Baroque orchestra. Soloists for Sunday’s performance included singers who had a history with Pro Musica, as well as newcomers. Soprano Mary Ellen Callahan had her hands full with a very quick “Laudamus Te,” but handled the tempo well without feeling rushed. Ms. Callahan was well matched with mezzo-soprano Alyson Harvey, with whom she shared two duets. These two singers were especially cognizant of each other in the “Et in unum Dominum” duet, as phrases flowed among singers and violins.

Ms. Harvey had two very tough arias, closing phrases particularly well in the mezzo aria from the “Gloria” section. Her phrasing never felt rushed, despite the difficulty of the passages, and she was elegantly accompanied by oboe d’amore player Caroline Park. Ms. Harvey was also key in closing the entire mass, singing a haunting yet crystalline “Agnus Dei” which summed up the imploring text leading up to this point and making the final chorus all the more glorious.

Tenor Robert Petillo brought a long history of Bach performance to this concert, drawing on his experience as a Bach passion evangelist to present the “Benedictus” text with the authority of a preacher, as the flute obbligato, gracefully played by Mary Schmidt, chased the vocal phrases. Mr. Petillo collaborated well with Ms. Callahan in a duet from the “Gloria,” with Mr. Petillo handling well some unusually quirky word placement. Bass Kevin Deas, who has been heard with Pro Musica numerous times, was as commanding as he has been in previous performances, maintaining especially well the long vocal lines of “Et in spiritum sanctum.” In this aria Mr. Deas was accompanied by two oboi d’amore (played by Ms. Park and Nathan Mills), which was a special treat since it is rare enough to hear one oboe d’amore, much less two. In a previous choral section, Ms. Slade wisely re-assigned a very difficult bass choral line to Mr. Deas, who presented the resurrection text with affirmation and conviction.

More than anything else, this performance was about Pro Musica and what Frances Slade has created over the past thirty-three years. The choral movements were full of the trademark Pro Musica blocks of sound, with especially clean runs in very quick tempi. As could be expected, the vocal musicians sang their hearts out, and the sections were always well-balanced. Most energetic among the choral movements was the “Et expecto” section which closed the “Symbolum Nicenum,” with the chorus flying through runs and three trumpets adding a joyous touch. As also should have been expected, all performers, and especially Ms. Slade, were clearly pleased with themselves as the ensemble celebrated its past and looked toward new beginnings.