Fergus mac Róich

Fergus mac Róich (son of Ró-ech or "great horse"; also mac Róig, mac Rossa) is a character of the Ulster Cycle of Irish mythology. Formerly the king of Ulster, he is tricked out of the kingship and betrayed by Conchobar mac Nessa, and becomes the ally and lover of Conchobar's enemy queen Medb of Connacht, and joins her expedition against Ulster in the Táin Bó Cúailnge. The name Fergus (later Irish Fearghus) means "man-strength" or "virility", and Fergus is described as being of enormous size and sexual potency. This leads him into many a precarious situation as in the story of the Táin Bó Flidhais.