A New York appeals court will begin hearing a landmark case on Wednesday that could determine if a chimpanzee has a legal status akin to personhood, thereby making its captivity unlawful.

Animal rights lawyer Steven Wise filed the lawsuit in 2013 on behalf of Tommy, a 26-year-old chimpanzee kept by a private owner in upstate New York. The lawsuit alleged that keeping the chimpanzee in captivity was unlawful, because a chimpanzee was not merely a possession of the owner, but rather “a cognitively complex autonomous legal person with the fundamental legal right not to be imprisoned.”

As such, the case called upon the court to grant Tommy the status of “legal personhood,” thereby extending the fundamental human right of habeas corpus, or the right to not be unlawfully imprisoned, to a primate.

The case grabbed headlines, including TIME’s, for its ambitious attempt to blur a longstanding legal distinction between humans and animals. The organization pressing the case, the Nonhuman Rights Project, has stated that the case will not end with Tommy: “Our goal is, very simply, to breach the legal wall that separates all humans from all nonhuman animals.”

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