Fleming Begaye Sr., a Navajo code talker who helped the Allies gain victory in the Pacific Theater in World War II, died on May 10, 2019 at the age of 97. He was one of the last remaining members of an elite group of Navajo people who used their language to help transmit top-secret military information during the war.

Born in 1921 in Red Valley, Arizona, Begaye attended a Native American boarding school—part of a United States policy that forced Native American children into schools that focused on English-only education. But the language of Begaye’s people, the Navajo (Diné in Navajo) would end up playing a major role in Begaye’s life. When World War II started, Begaye’s daughter tells The New York Times, Begaye heard the Marines were searching for people who could speak Navajo.

He answered the call and became part of history. During World War I, Choctaw code talkers had proven that Native American languages—which had few speakers due to U.S. policies that forced assimilation and drove Native Americans out of their traditional lands—could be used as an uncrackable code.

In World War II, the Marines used that tactic again, recruiting speakers of Navajo and other languages to send and receive messages on the battlefield. Navajo is unwritten and complex, and tests revealed that it was a quick and effective way to transmit vital information in the field.

Begaye was one of up to 420 Navajo men who served as code talkers. They were deployed to the Pacific Theater. There, Begaye fought in the Battle of Tarawa, a 76-hour battle to seize a Japanese-held island that left more than 3,000 U.S. troops dead or wounded. During the 1943 battle, the landing craft that was taking Begaye to shore was destroyed by a Japanese bomb. Begaye survived by swimming for his life.

The next year, Begaye almost died when he was shot while landing on Tinian in the Mariana Islands. The tiny island was home to a Japanese fortress, and Allied troops eventually turned it into an Air Force base. Begaye was in the hospital for nearly a year as he recuperated from the shooting.

After the war, the code talker returned to the Navajo Nation in Arizona, where he farmed and began a trading post, Begaye’s Corner. It took decades for the Navajo code talkers’ service to become public knowledge after information on the program was declassified in 1968. In 2017, Begaye and other surviving code talkers were honored by President Donald Trump in a controversial event in which the president taunted Senator Elizabeth Warren.

“Code Talker Begaye was a warrior, a family man, and a business man,” said Navajo Nation president Jonathan Nez in a statement about Begaye’s death. “In every aspect of his life, he was a loving person who cared greatly for his people.” Today, fewer than 11 code talkers are thought to still be alive.