The Boston Camerata, founded in 1954, has outlasted most other early music groups started around the same time, as well as many that have come and gone since, and it has contributed significantly to Boston’s reputation as this hemisphere’s most vital center of pre-Classical era, period instrument performance.

The ensemble has evolved considerably: Its repertory was once drawn almost entirely from European Medieval through Renaissance works, but during the last couple of decades of lutenist Joel Cohen’s directorship, the group began expanding its view with programs that explored the nexus of Christian, Jewish and Muslim music in 15^th century Spain, or early American music. Ann Azéma, the mezzo-soprano who has directed the ensemble since 2009, has maintained, refreshed and expanded on many of those projects, and added productions of her own.

The singers and instrumentalists of the Camerata came to Hannaford Hall on Sunday afternoon, joined by the Middlesex County Volunteers Fifes and Drums, and one of the finer Portland choirs, St. Mary Schola. The program, presented by Portland Ovations, which has brought the group here four times previously, is based largely on “Free America! – Early Songs of Resistance and Rebellion,” the ensemble’s superb new album (on Harmonia Mundi).

The program offered 34 vocal works and marches, mostly from the decades between the American Revolution and the Civil War. Political broadsides, as well as sacred songs and spirituals – and combinations, in which political aspirations for the then-new country are interwoven among religious sentiments – were grouped into thematic sections. One grouping was built around Shaker songs (the source for pieces in some of the other groupings as well), and there was a pre-concert talk about the Shakers’ use of music by Brother Arnold Hadd, of the Sabbathday Lake Shaker community.

Familiar colonial-era composers like William Billings (via “Chester” and “David’s Lamentation”) and Jeremiah Ingalls (“The Rich Man” and “A Land of Freedom”) make appearances, and a few songs have texts by the likes of Thomas Paine (“Liberty Tree”) and Joseph Warren (“Free Americay!”). But most were anonymous, or drawn from antique published collections, although even a few of those have remained virtually current, including the bittersweet ballad “Johnny Has Gone For a Soldier” and “Yankee Doodle,” which was performed at the beginning and end of the program, as the musicians took and left the stage.

All of which is to say that it would be hard to find a more comprehensive or varied two-hour overview of this repertory, or one performed with greater polish, passion and zest. You might raise a historical quibble here and there. For example, you might have found yourself wondering whether the singers of the time really brought the kind of nuance (like the careful rallentando ending of “Friendly Union”) that the Camerata musicians applied to what were essentially rough-hewn folk tunes and congregational church hymns.

On the other hand, performances that might have seemed a little odd – the unaccompanied vocal versions of a march and an untitled dance tune, in the set of Shaker pieces – were actually historically apt, since Shaker music was typically entirely vocal.

In the non-Shaker pieces, there is considerable leeway in how the music can be performed, and Azéma and company took every opportunity to vary the settings while keeping the music flowing smoothly. Unaccompanied vocal pieces (solos, duets, trios and choral settings) sat beside those accompanied by combinations of violin, flute, cello, fifes and percussion, and occasionally, arrangements would cycle through the possibilities, with instrumental, solo vocals and choral settings alternating.

Musically, the point that emerged most strikingly is the degree to which this music stood apart from the European mainstream. It was not only a matter of its folk influences, or its political rambunctiousness. Though these were mostly late 18^th and early 19^th century works, the harmonic language was often closer to the style of the late 16^th century, or earlier. But they were not purely 16^th century harmonizations; the folk elements pushed them in directions that European composers did not take.

This was the Boston Camerata at its best, performing music that has largely been overlooked, in an illuminating and thought-provoking way. If you missed it, or if you attended and loved it, there is more on disc – not only the new album, but several earlier Camerata recordings as well, among them “Liberty Tree – American Music 1776-1861,” “New Britain: The Roots of American Folksong” and “Simple Gifts – Shaker Chants and Spirituals” (all on the Erato label).

Allan Kozinn is a former music critic and culture writer for The New York Times who lives in Portland. He can be contacted at: allankozinn@gmail.com

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