PHILADELPHIA (AP) — Federal authorities say 15 historical artifacts stolen almost a half-century ago from a number of Pennsylvania museums have been returned to the institutions. The FBI’s Philadelphia office said the FBI art crime team and other law enforcement agencies repatriated the 18th and 19th century rifles and pistols as well as a Native American silver concho belt in a ceremony Friday at the Museum of the American Revolution. FBI art crime agents and detectives from the Upper Merion Township Police Department recovered the artifacts as part of an investigation into the 1971 theft and 2018 sale of a rare surviving 1775 rifle made by Pennsylvania master gunsmith Christian Oerter, officials said.