GREAT BARRINGTON — If you plotted the rise and fall of the violin and viola da gamba on a graph, it would show the violin line going up and the gamba line headed down.

That, at least, was the premise behind Aston Magna's program of late 16th-century and early 17th-century music on period instruments Saturday evening at Saint James Place. Violinist-director Daniel Stepner's program notes portrayed the violin back then as a commoner's instrument, fit for fiddling in taverns. The gentler, knee-clasped gamba, with a lower range, was the aristocratic opposite, a favorite in Europe's courts.

Over time, the graph lines crossed: for the violin, a rise to modern eminence; for the gamba, a decline from grace.

"We violinists need to be reminded occasionally that historically we were interlopers in the realm of `serious,' cultured instrumental music, of which the regal gamba was emblematic," Stepner wrote.

On paper, the concert's thematic basis looked esoteric, even didactic. In practice, the seven pieces proved surprisingly varied and sophisticated. Six Aston Magna musicians animated the performances with enthusiasm, versatility and mastery in works ranging from solos to sonatas employing the full complement. Violin and gamba emerged as equals. (But don't ask about the time-outs for tuning.)

Among the seven composers, only Leclair, Marais and Couperin are regulars on the early-music circuit. Several composers also proved mysterious or provocative with their programmatic titles, sometimes leaving not a clue to their meaning.

A "concert" for two gambas by Sainte-Colombe (no first name), titled "Tombeau Les Regrets," was pretty clearly an elegy leading to the Elysian Fields. Sarah Cunningham and Laura Jeppesen winningly made the journey. Less clear in meaning - downright baffling, in fact - were two closing pieces by Couperin: "Les Barricades Mysterieuses," a harpsichord solo, and "La Sultane," an intricate sonata calling on the services of all six players (the violin and gamba parts were doubled).

If the Sultan's portrait contained not a whiff of hashish or the harem, the pleasures of performance sufficed. Michael Sponseller was the agile harpsichord soloist.

The evening's most striking work was a sonata by Dario Castello that opened the program. Also played by the full group of six, its abrupt shifts between sections and from instrument to instrument sounded at times like an argument between violin and gamba. Then lyrical passages subsided into genial agreement.

Oh, and there was a lively violin duo by Leclair, with Stepner and Edson Scheid batting ideas around like shuttlecocks. Sainte-Colombe's "tombeau" (tomb, or memorial) contained a flowing lyrical theme that could have been mistaken for Bach. Catherine Lidddell spun enchantment out of "Les Sylvains," a gentle, madrigal-like solo for theorbo (long-necked lute) by Robert de Visee. Around and around the sylvans' melody went, little changing.                                                                                                                                                                

Though transported to a concert hall, these pieces easily evoked sights and sounds of European courts with lords and ladies assembled before the king or duke for an evening of entertainment. The program was dedicated to the memory of John Hsu, a champion of the gamba and former artistic director of Aston Magna.