We know that the angels were created prior to the Earth. We find Satan had already fallen in Genesis 3. The mystery is, when did he fall? It appears that there are substantial scriptural references to his rebellion, his agenda, and the subsequent catastrophic judgment that ensued.
This raises the whole issue of the origin of evil. And why hasn’t God simply wiped him—and sin—out completely? It is also disturbing to recognize that Satan tempted Jesus by offering him the “kingdom, power and the glory” in the temptations recorded in Luke 5 How could Satan lay a legitimate claim to these?