Kultida Woods, the mother of 15-time major champion Tiger Woods, died Tuesday morning. She was 81.

Her son announced the news of her passing on social media shortly before noon ET, just a week after she attended her son’s most recent TGL match in Palm Beach, Fla. The cause of death was not announced.

“It is with heartfelt sadness that I want to share that my dear mother, Kultida Woods, passed away early this morning,” Woods said in a statement shared to social media. “My Mom was a force of nature all her own, her spirit was simply undeniable. She was quick with the needle and a laugh. She was my biggest fan, greatest supporter, without her none of my personal achievements would have been possible.”

“Tida,” as she was called for much of her life, was a central figure in the life of the greatest golfer of the modern era — a fierce and stoic woman who shepherded her only son into the world spotlight as a teenager, and who followed closely behind as he traversed a path to 15 major championships and 82 professional victories.

Born in Thailand in 1944, Tida’s life changed when she took a job as a secretary on a military base at the height of the Vietnam War in the 1960s. At work, Tida met a U.S. Special Forces soldier named Earl, and the two quickly fell in love. She followed Earl back to New York, and again to Cypress, Calif., where the couple decided to settle down. In 1975, they welcomed their first and only child into the world, a boy, and named him Eldrick — E, for the first letter of Earl’s name, K, for the first letter of Tida’s.

While Earl would later earn great acclaim for his role as Tiger’s first swing coach and mentor, Tida’s role in her son’s development was no less significant. She was Tiger’s shadow for much of his early life, chauffeuring her son to junior golf events and walking the fairways alongside him. Later, she was the driving force behind Tiger’s iconic “Sunday Red” attire, believing that Woods’ astrological sign, Capricorn, made red his “power color.”

“My mom doesn’t get enough credit,” Woods said at the Bob Jones award dinner last June. “Everyone thought that it was my dad when I went on the road, which it was, but Mom was at home. If you don’t know, Mom has been there my entire life.”

In her later years, Tida Woods also assumed the role of matriarch of Tiger’s inner circle, attending her son’s events with vigor into her 81st year. On Sundays, including on the Sunday of Woods’ last Masters start, she could be spotted matching her son’s vibrant red and black.

“She was loved by so many,  but especially by her two grandchildren, Sam and Charlie,” Tiger said in his statement. “Thank you all for your support, prayers and privacy at this difficult time for me and my family. Love you Mom.”

Kultida Punsawad Woods is survived by her son, Tiger, and grandchildren, Samantha and Charlie.