Facebook, the wildly popular social networking site, may soon be squaring off in federal court in Philadelphia to defend itself against claims that the site’s design infringes on a patent that was filed several years before Facebook was launched in 2004.

In the suit, plaintiff Cross Atlantic Capital Partners, also known as XACP, claims that it holds the rights to a patent for an Internet-based “community for users with common interests to interact in” that was invented in 2000.