A baseball signed by Babe Ruth during the 1926 World Series sold at an auction for $250,641 Thursday night.

The ball is considered one of the most famous because it was autographed by Ruth with a promise to hit a home run for an ailing 11-year-old boy.

It was sold by Grey Flannel Auctions. An official with the auction house told ESPN that the buyer requested to remain anonymous.

The boy, Johnny Sylvester, who was injured after falling off a horse in the summer of 1926, received the autographed ball with the message: "I'll knock a homer for Wednesday's game" written on it.

Ruth then hit three home runs for the New York Yankees that night, which was Game 4 of the World Series. Newspapers reported at the time that Sylvester's condition suddenly improved after Ruth hit the homers.

The ball was owned by Sylvester's son, John Jr., and on loan to the Babe Ruth Birthplace and Museum in Baltimore for 25 years.

It sold on the 119th anniversary of Ruth's birthday. Ruth, who died in 1948, remained in touch with Sylvester until his death. Two letters written by Ruth to Sylvester sold for $76,747 and $71,553 at the auction.

In 2012, another ball signed by Ruth sold for $388,375.