Medical encyclopaedist Aulus Cornelius Celsus was a landed gentleman. He wrote the six-volume De Medicina (c.30AD), a compilation of received wisdom about diet, pharmacy and surgery in early Imperial Rome. In De Medicina, Celsus describes "anodyne pills" that alleviate pain by inducing sleep. Anodyne pills were prepared by brewing opium poppy and then mixing it with wine. Celsus gives instructions on their judicious use.
In Volume 111 of De Medicina, Celsus observes that opium juice "has been used to calm tempers and to induce pleasant dreams since the Trojan War and is still popular." However, "doctors should use it with circumspection". For "dreams can be sweet, but the sweeter they are, the rougher tends to be the awakening."
Refs and Further Reading
Anaesthesia and Anaesthetics