The first burglary was in 1999 at Keystone College in Factoryville, Pa. One of the gang, authorities said, sneaked onto the campus, smashed some glass display cases and walked off with memorabilia, including a baseball jersey once worn by Christy Mathewson, the legendary pitcher.

The Everhart Museum in Scranton was next, six years later. An Andy Warhol silk screen print and a painting attributed to Jackson Pollock were taken. Then the pace picked up.

The Space Farms: Zoo & Museum. The Lackawanna Historical Society. Ringwood Manor. The Sterling Hill Mining Museum. The United States Golf Association Museum and Library.

The list goes on.

Over the course of almost two decades, the crew showed up at 12 small, low-profile museums that often lacked elaborate security systems, stripping them of cherished items, including treasured heirlooms from America’s sporting past, authorities say.

Just a partial list includes — from the National Museum of Racing and Hall of Fame — the 1903 Belmont Stakes trophy. From the International Boxing Hall of Fame, middleweight Tony Zale’s 1941 and 1948 championship belts. From the Yogi Berra Museum & Learning Center, seven of Berra’s championship rings, his 1954 and 1955 M.V.P. plaques, and nine of his 10 World Series rings.

The only Berra World Series ring not stolen was the one he wore on his finger.

“These kinds of artifacts tell people the story of who we are, and they connect us to the past in a way that really nothing else can,” said Eve Schaenen, executive director of the Berra museum. “And now they’re gone.”