Babe Ruth's own copy of his 1918 contract with the Boston Red Sox sold for $1m in a dedicated sale at Goldin Auctions in New Jersey on July 12.
The lot is one of three copies the star signed, one of which is owned by the Red Sox. The other belongs to the American League - meaning this is the only example on the private market.
Goldin explained the significance of the lot prior to the sale: "This contract, the Babe's own, is the only 1918 that has survived and is the earliest Babe Ruth Player's Contract known!
"The historical significance of the year 1918 to Ruth scholars is paramount - that was the year he began the transition from ace pitcher to the slugger he became known as."
A signed Louisville Slugger bat used during the 1918-1920 season sold for $420,000.
Ruth took the bat with him when he left the Red Sox for the Yankees and used it extensively during his early seasons. It was later bought by collector Eddie Maier and is inscribed "To My Friend Eddie Maier from Babe Ruth".
In addition to the signature, the bat is marked from where it has made contact with the ball and shows cleat marks from where Ruth used to knock the mud from his boots.
On July 31, a Yankees cap belonging to Lou Gehrig is expected to make more than $200,000 at Heritage Auctions.
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