UNITED NEWS INTERNATIONAL (UNI) — Anna Mae Hays, an Army nurse who was named the U.S. military’s first female general after serving in three wars, has passed away.

Hays joined the Army in 1942, working in the China-India-Burma theatre before treating people during the Korean War.

She eventually rose to oversee the Army Nurse Corps through the bloodiest years of the Vietnam War.

Hays made history when she was promoted to brigadier general on June 11, 1970, becoming the first female general ever in the U.S. military.

She used her role to advocate for women in the military and was instrumental in the establishment of maternity leave for female officers.

Hays died of complications from a heart attack on Jan. 7 in Washington, D.C. She was 97.

Pennsylvania Gov. Tom Wolf ordered the state flag to fly at half staff to honor Hays, who grew up there.