After some 290 years of existence, J.S. Bach's Brandenburg Concertos would be expected to have found some sort of optimum manner of performance. And they seemed to until the last decade, when this music became a repertoire crossroads in the early music world. Each new group built on the strengths of the last, rendering once-classic recordings obsolete and ones made in even less-enlightened times (such as those sleepy, old things conducted by Pablo Casals) borderline unlistenable.

Into this fray came the season finale of Tempesta di Mare's Brandenburg year, in which all six of the concertos were played in juxtaposition with the composer's like-minded contemporaries. Though it has been around since 2002, the group hasn't the level of government subsidy or larger community of musicians to enter that speedy, supervirtuosic circle inhabited by Concerto Italiano or the Swiss Baroque Soloists. But one does need to be seriously grateful for the chance to be in the same room with the sort of intelligent, authentic-instrument performances heard Saturday at St. Mark's Church.

Take the small, strange sixth Brandenburg, for example. Without violins, winds, or catchy tunes (at least until the final movement), the concerto can seem startlingly gray. Tempesta di Mare achieved a lean, cutting sonority with a wiry string tone (seeming to bow closer to the bridge of their instruments) that more readily drew your ear into the piece's inner workings. The sequential repetition (similar to baroque church architecture) had a hypnotic effect similar to the minimalism of Philip Glass - even when the performance of the final movement got a bit messy. The scintillating Brandenburg Concerto No. 4 ended the concert with generously full sonority - and a happy audience.

Though programming alongside Bach always risks unflattering comparison, the often-dull Georg Philipp Telemann and the little-known Evaristo Felice Dall'Abaco more than held their own, that last composer having a Vivaldi-esque taste for emphatic musical ideas, yielding a piece that felt like an intriguing, purposeful series of fragments. Though Tempesta di Mare has championed little-known baroque composers such as Sylvius Leopold Weiss and Johann Friedrich Fasch, the greater rehabilitation achievement has been with Telemann, thanks to often revelatory choices from the composer's vast output. Suite in G, for example, has seven movements that seem to hail from completely different pieces - all of them leaving you wanting more. Double Concerto in E minor has a lovely pizzicato movement that showed soloists Emlyn Ngai (violin) and Gwyn Roberts (flute) making the most of their musical spotlights.

Contact music critic David Patrick Stearns at dstearns@phillynews.com.