Button depicts "A&HA" / "1638", Ancient & Honorable Artillery is a traditional militia unit from Boston, Massachusetts button, dating to well before the American Revolution and existing today as an fraternal military society. This flat two piece button was used around the Civil War for ceremonial purposes. Backmark: "D. EVANS & Co/ (star) EXTRA (star)"dm. Flat two-piece.
Reference: Albert MS47 Tice MS222
Inventory Number: BUT 027