Duke of Sparta (Greek: Δοὺξ τῆς Σπάρτης) was a title instituted in 1868 to designate the Crown Prince of the Kingdom of Greece. Its legal status was exceptional, as the Greek constitution forbade the award or acceptance of titles of nobility for Greek citizens. Consequently, it was mostly used abroad, although also in unofficial use within Greece. This led to a stormy debate in Parliament, but the government of the day backed the King on an argument that the constitutional provision did not apply to members of the Royal Family (even though its text made no distinction).