Korczak Ziolkowski, a Polish American sculptor, was a fiery-tempered man who devoted half his life to carving a monument to the Sioux warrior-chief Crazy Horse that promised to dwarf the presidential heads at nearby Mount Rushmore.

The work would be colossal, perhaps the largest modern sculpture in the world.

Ziolkowski began the task in 1948 after buying a granite peak in the Black Hills of South Dakota that he named Thunderhead Mountain. Crazy Horse defeated the cavalry of Col. George Armstrong Custer in the 1876 Battle of the Little Big Horn.

While Ziolkowski went about his undertaking on a shoestring — he refused offers of federal funding, saying it would be an insult to American Indians — he was supported unconditionally by his wife, Ruth, who died Wednesday at 87. She lived with him in a log house, bore 10 children and tended to the museum and gift shop near the planned monument.

Korczak Ziolkowski designed the sculpture to be 641 feet long and 563 feet high, depicting Crazy Horse astride a wild stallion and pointing east in tribute to the burial place of many Sioux. The four presidents on Rushmore are 60 feet high. The Crazy Horse Memorial stallion’s eyeball alone is about 30 feet across.

Korczak Ziolkowski died in 1982, at 74, with much of the outline of the horse and rider visible but not finished. Ruth succeeded her husband as chief executive of the Crazy Horse Memorial Foundation and helped redirect efforts toward faster completion.

For years, her husband had focused on carving the stallion, but Ruth Ziolkowski felt it would speed fundraising if the face of Crazy Horse were done first. The image of Crazy Horse began to take shape in time for an official dedication in 1998 at a ceremony marking the 50th anniversary of the project’s inception.

Ruth Ziolkowski also expanded and developed the 1,000-acre site, which includes an American Indian history museum, a restaurant and the Indian University of North America, which works with the University of South Dakota to offer credits for college-bound high school students.

The site draws 1.2 million visitors annually, said a memorial spokesman, who confirmed the widow’s death from cancer at a Rapid City hospital.

The sculpture’s projected date of completion remains unclear.

Ruth Carolyn Ross was born June 26, 1926, in Hartford, Conn., and grew up in West Hartford, where her father was an insurance executive and noted amateur golfer.

Korczak Ziolkowski had been born in Boston and endured a hardscrabble early life before he began winning sculpting contests. He went to South Dakota in 1939 as an assistant to Gutzon Borglum, the eccentric visionary behind Mount Rushmore.

After Ziolkowski came to near-blows with Borglum’s son, the Polish American artist was persuaded by a Sioux leader, Henry Standing Bear, to build a competing monument. Standing Bear wrote to Ziolkowski, “We would like the white man to know the red men have great heroes also.”