R.E.M

Musically, they rely on safe folk-rock formulas that evoke everyone from R.E.M. to Gordon Lightfoot.

Lyrically, they visit other eras, suggesting the times of minstrels and troubadours and employing antiquated language, such as “piquaresque” and “infanta” and font such as the Barrow Boy and the Chimbley Sweep.

Monday night, the Decemberists visited the chic Theater and bestowed upon a crowd of almost 2,000 fans an amusing evening of music, history and literary inferences leavened by moments of whimsy, satire and good-hearted snarkiness. And the crowd, which was wound up from the start, loved every minute of it, even the cheesy, recorded foreword by the mayor of Portland, Ore., the band’s hometown.

Colin Meloy is the Decemberists’ lead vocalist, songwriter, master of ceremonies and head of its ship, which integrated special visitor Sara Watkins. For a band that delves into material that could collapse under the weight of all its intellect and ornateness, he and his mates manage to keep things light and lively.