TT #62 · Parashas Noach · Fifth Aliyah · Passuk 9:25
And he said: “Cursed be Canaan; a slave of slaves shall he be to his brothers.”
Torah Temimah points to the episode of the African claimants before Alexander (Sanhedrin 91a).
E-Daf image — Sanhedrin 91a (size=3)
English: “A slave of slaves” — When the Africans came to litigate with Israel… Geviha ben Pesisa said to them: “It is written ‘Cursed be Canaan, a slave of slaves shall he be to his brothers’ — a slave who acquires property: the slave belongs to whom, and the property to whom?”
Custom (application of the curse to a territorial claim).
The status of Canaan as “slave of slaves” was invoked to refute a claim to the Land of Canaan by descendants of Cham.