The mother of former Secretary of Defense James Mattis died Sunday at the age of 97.

Lucille Mattis was born on 1922 in Winnipeg, Canada. Her family immigrated to United States a year later, where she moved to Washington, D.C., in 1941 to work as a stenographer in the War Department as a civilian employee of Army Intelligence.

While traveling on a ship to South Africa after being assigned to the Office of the Military Attache at the U.S. Legation, she met her future husband, West Mattis, a merchant mariner. They married after the war and had three sons, Gerald, James, and Tom.

The family described her as a "fiercely independent woman who exemplified the spirit of the women of her generation — shaped by the Great Depression, tempered and forever marked by their monumental contributions to our nation during the Second World War."

Most famous of the trio, James Mattis, served in the Marine Corps for more than 40 years, earning popularity in the ranks before being tapped to serve as secretary of defense by President Trump. Mattis has been a lifelong bachelor, earning the nickname Warrior Monk, in addition to his large personal library.

His brother, Tom, was the first of the family to join the Marines. He served for six years starting in 1967 and did a 14-month tour of duty in Vietnam with an artillery battalion. His other brother, Gerald, is a senior functional analyst in Washington state.

He was secretary of defense until he submitted his resignation because of disagreements with Trump over troop withdrawals from Syria and Afghanistan.

During his confirmation hearing, Mattis talked about his mother's experience working in the Pentagon during World War II.

"She had come to America as an infant and lives today on the banks of the Columbia River in the Pacific Northwest. Little could she imagine in her youth that more than 90 years after she immigrated to this country and 75 years after she first walked through the doors of the War Department, one of her sons would be sitting here in front of you today," he said.

When asked if he had family members with him in Washington, D.C., Mattis replied, "They are safely west of the Rockies."