The whole of the prophets and apostles عليهم الصلاة والسلام have preached monotheism to his people in every period (generation) it. As Allah says:
Oo dhan ayaa ka mid ah nebiyo iyo rasuullo عليهم الصلاة والسلام wacdiyey tawxiid qoomkiisii isagoo muddo kasta (Qarni) waxaa. Sida Eebe wuxuu leeyahay,