Agrippina the Younger outraged by Claudius' adoption of Nero and his choice of Nero as successor, instead of choosing his own son Britannicus. Nero and Octavia were married on June 9, 53. Claudius later repented of marrying Agrippina and adopting Nero, began to favor Britannicus, and started preparing him for the throne. His actions allegedly gave Agrippina a motive to eliminate Claudius. The ancient sources say she poisoned Claudius on October 13, 54 with a plate of deadly mushrooms at a banquet, thus enabling Nero to quickly take the throne as emperor. Accounts vary wildly with regard to this private incident and according
Vipsania Marcella Vipsania Marcella Vipsania Marcella Agrippina or Marcellina or Vipsania Tertia (born 27 BC or later) was perhaps the only daughter of Roman statesman Marcus Vipsanius Agrippa by his second wife Claudia Marcella Major. If so, she was the first grandchild to Octavia Minor and first great-niece to Roman Emperor Augustus. If she truly had the name Marcella, there is no way that she was a daughter of Agrippa's first wife, Caecilia Attica. She and her elder sister Vipsania Agrippina were married off to Quintus Haterius (cos. 5 BC), Publius Quinctilius Varus (cos. 13 BC) and Tiberius (also cos. 13 BC)