Before the fall of Lucifer he had a throne, a kingdom and subjects to rule. His kingdom was under the stars, the clouds, and under heaven on earth. He took one third of Heaven’s angels and tried to overthrow God and His Kingdom. All this had to be before Adam came into existence, for no such thing has happened since Adam was made. According to Ezek 28: 11-17 Lucifer was an Anointed cherub or protector of the earth, being full of wisdom and perfect in beauty, ruling in a Garden of Eden before Adams’ time. He was created by God and perfect in his ways until sin entered in to him. You have the reasons for the fall and the results of the fall, which would have to be before Adam. Again proving a pre-Adamic world.