 On 18 September 96 , <unk> was assassinated in a palace conspiracy involving members of the <unk> Guard and several of his freedmen . On the same day , <unk> 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 <unk> government of <unk> . 
