Short answers, pulled from the story.
Seneca the Younger was a Roman Stoic philosopher, statesman, and dramatist who lived from around 4 BC to AD 65. He served as advisor to the emperor Nero and produced 12 philosophical essays, 124 moral letters, and eight tragedies that shaped Stoic thought, Renaissance drama, and Elizabethan tragedy for centuries.
In AD 41, the empress Messalina accused Seneca of adultery with Julia Livilla, sister to Caligula and Agrippina. The Senate sentenced him to death; Emperor Claudius commuted the sentence to exile. Seneca spent the following eight years on the island of Corsica.
Seneca served as Nero's tutor from AD 49 and as his chief advisor alongside the praetorian prefect Sextus Afranius Burrus from AD 54 to 62. He wrote Nero's accession speeches and composed On Clemency to guide him toward Stoic virtue. His influence declined after Burrus's death in 62, and in AD 65 Nero ordered him to die following the Pisonian conspiracy.
In AD 65, Nero ordered Seneca to kill himself following the Pisonian conspiracy to assassinate the emperor. Seneca severed veins to bleed to death, but his age and diet slowed the process. Poison also failed to kill him. He finally died in a warm bath, where steam suffocated him, with friends and a scribe present.
Eight tragedies are almost certainly by Seneca, including Thyestes, Medea, Phaedra, and Oedipus. All ten plays attributed to him were published together in English translation in 1581. They are considered the source of the Revenge Tragedy genre and influenced William Shakespeare, Corneille, Racine, and Joost van den Vondel.
The church leader Tertullian called him "our Seneca," and by the 4th century an apocryphal correspondence between Seneca and Paul the Apostle had been created. Jerome included Seneca in a catalogue of Christian writers, and the 13th-century Golden Legend featured an account of his death. Some medieval scholars concluded he must have been a Christian convert.