Corinthian bronze, also named Corinthian brass or aes Corinthiacum, was a highly valuable metal alloy in classical antiquity.  It is thought to be an alloy of copper with gold or silver (or both), although it has also been contended that it was simply a very high grade of bronze, or a kind of bronze that was manufactured in Corinth.  It is referred to in various ancient texts, but no certain examples of Corinthian bronze exist today.  However, it has been increasingly suggested that a number of artefacts previously described as niello in fact use a technique of patinated metal that may be the same as Corinthian bronze and is similar to the Japanese Shakudō.
Its composition was long a mystery, but contemporary thinking is that Corinthian bronze was "a patinated alloy of copper with some gold and silver", perhaps the same as the hesmen kem or "black copper" of Ancient Egyptian art.  This is shown by ancient texts to be a prestigious material, and apparently survives in a number of statuettes of "distinctive black-patinated, inlaid metal", of which scientific analysis shows "that some have a highly unusual composition containing small amounts of gold, silver and arsenic in the alloy", and are broadly similar to Shakudō.