text:  On 18 September 96 , Domitian was assassinated in a palace conspiracy involving members of the Praetorian Guard and several of his freedmen . On the same day , Nerva was declared emperor by the Roman Senate . This was the first time the Senate elected a Roman Emperor . As the new ruler of the Roman Empire , he vowed to restore liberties which had been curtailed during the autocratic government of Domitian . 
  