The Concord Chorus, under the direction of Dr. Kevin Leong, presents Joseph Haydn’s “Maria Theresa Mass” on May 20, 8 p.m., at the spacious St. Camillus Church, 1185 Concord Turnpike, Arlington. This soaring and lyrical work for chorus, solo quartet, and orchestra, composed in 1799, is the fourth of Haydn’s six monumental Late Masses. From the work’s stately opening to its gentle close, Haydn infused his “Maria Theresa Mass” with exceptional warmth and great power. Dr. Leong: “To be sure, the Theresienmesse is also a work of great contrast and power, and it is unfortunate that it has been historically underappreciated. It is the only one of Haydn’s Late Masses not published during his lifetime.” The Concord Chorus, a nonprofit organization founded in 1945, occupies an honored place in the musical life of Concord, Massachusetts, and surrounding communities.  Come out for a lovely evening of music and pick out a few of your Bedford neighbors in the chorus. Tickets are $30 adults, $25 seniors, $10 children and students and are available at concordchorus.org or (978) 254-1759.