That “museum” in the subtitle of “Brilliant Beginnings: The Athenaeum and the Museum in Boston” isn’t generic. It refers to the Museum of Fine Arts.
Long one of the world’s great art institutions, the MFA didn’t start out that way. It began in the shadow of and was much beholden to another local cultural establishment, the Boston Athenaeum. The early relationship between them is the subject of this charming, handsomely mounted show, which runs at the Athenaeum through Aug. 3. The show’s small size (not quite 70 items) enhances that charm.