An 1860 Brooklyn Atlantics baseball card is among the highlights of a major sports memorabilia sale at Heritage Auctions.

The lot is valued in excess of $50,000 ahead of the July 30 sale at the National Sports Collectors Convention in Chicago.

The Brooklyn Atlantics were early baseball's greatest team

It's among the most important pieces of early baseball memorabilia ever to come to auction and is one of only two known specimens in existence.

Chris Ivy, director of sports auctions at Heritage, explains: "This is a seminal artifact, not just of baseball, but of American history.

"It ranks with the most significant mementos of the sport's infancy ever to surface and is, quite possibly, the only team card on Earth printed before the first drop of blood was spilled in the American Civil War."

The Brooklyn Atlantics were founded in 1855 and disbanded in 1882. They were the first champions of the sport, and won seven pennants in the 1850s and 1860s.

Another baseball card featuring the team, dating to 1865, sold for $92,000 at Saco River Auction Co in 2013.

You can check out all our sports memorabilia for sale here.

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