Yes, Augustus was a princeps, theorically a primus inter pares (I said theorically =)). In Italy we use "Principe" and "Principato" when refering to him, which are, in my opinion, the correct forms to use. However in present days the word Imperator (more specifically emperor) acquired a different meaning from the one it had at the time of Augustus, so all in all this "significant" carries an acceptable meaning..sorry for my English