History Memes

Interesting enough, he was given the title "Pius" by the Senate after he was appointed Emperor, because of his actions towards his adoptive father, Emperor Hadrian, even rushing to stop him from committing suicide and physically supporting him when he had trouble standing. After Hadrian's death the Senate, who never liked Hadrian all that much (and the feeling was mutual on Hadrian's part), was eager to move on from Hadrian's rule; Antoninus, however, insisted on honoring his adoptive father in the traditional way.

Because of this, while the Senate was not thrilled at honoring Hadrian, it was seen as a remarkably filial thing for a man to do who could have very easily garnered political support by simply refraining from doing so. As Roman society valued respect for one's father (adoptive or otherwise) very highly, the Senate bestowed on him the name 'Pius' - 'Morally Dutiful'.