The next year Claudius married his niece Agrippina the Younger. In AD 50 Claudius adopted him as Nero, and the older Nero soon took precedence over Britannicus. Tacitus and Suetonius report that Nero had him poisoned. Britannicus was poisoned at a dinner party attended by his sister, Octavia, Agrippina and several other notables. Tacitus' account of the event is that Britannicus was given a hot drink, which was tested by a food taster, and when he asked for it to be cooled, the poison was added to it with the cold water. The substance was instantly effective, and he "lost alike both voice and breath". Nero claimed to those present that Britannicus was merely experiencing an epileptic seizure and that he had been affected by the condition since childhood. He died sometime between December 54 and 11 February 55, the day before his 14th birthday, when he was to assume manhood, just four months after his father's death. For her service, the emperor had Locusta rewarded with large estates and even sent her pupils. The available biographical account does not describe a continuous final medical course. It gives no dependable sequence of treatment and last symptoms from which to reconstruct a more detailed bedside narrative.