Beethoven’s string quartets are grouped into three categories — early, middle, and late. One might be forgiven for listening to an early Beethoven quartet and believe one is listening to Haydn or Mozart. Beethoven was influenced by the classical composers in the early part of his career, as was everyone else who was writing at the time. His middle period work is much more romantic and expressive. Beethoven was strongly influenced by early romantic composers, including C.P.E. Bach, and others, which is why Beethoven is widely accepted as one of the few composers who is considered to straddle both styles. However, his late period work is pure Beethoven, a style unto itself. Many have emulated the mature Beethoven, but no one is thought to be a member of the same musical school.

The Bowdoin International Music Festival is performing all 16 of Beethoven’s string quartets (and the Grosse Fugue that had originally been part of the 13th string quartet but which is now considered its own work) over six Mondays.

On July 7, one of the Festival’s guest performers, the Brentano Quartet, tackled Quartet 3 in D Major, Op. 18 No. 3, from Beethoven’s early period; Quartet 11 in F Minor, Op. 95 (Serioso), from his middle period; and Quartet 14 in C-sharp Minor, Op. 131, from his late “Beethoven” period.

The quartet’s style was not your grandfather’s string quartet style. In the first piece, the early piece, the Brentano quartet were more than playing instruments together; it was a great dance ensemble.

In the first movement, a series of dramatic attacks were performed both musically and physically as one. The effect was electric and percussive.

The piece recalled even earlier musical styles, with stepped dynamics in the second movement, opposed to crescendo that was certainly in use at the time of its writing.

The second quartet, No. 11, the Serioso, initially felt more baroque than romantic, but soon enough, the piece morphed into a very romantic work.

No. 14, one of the late works, was pure Beethoven. Starting out with an homage to the

Well-tempered Clavier and Bach’s Art of the

Fugue in the first movement, it finishes gloriously with elements of the Fifth and Ninth Symphonies in the final movement, spanning the rest of musical tradition in the intervening movements.

The piece has heavy vibrato, but a minor but persistant buzz developed in the cello — perhaps a loose fine tuner — sometime around the second movement, and there was no way to repair it as the quartet danced its way to the finale. Despite that distraction, the Brentano Quartet delivered a fine, spirited performance, and was a delightful addition to the Festival.

The Beethoven Mondays will continue next week with the Ying Quartet playing Quartets 2, 4, and 15. Performances take place at Crooker Theater at Brunswick High School, at 7:30 p.m.