September-October-November-December: 7-8-9-10 And July used to be Quintilis (5) and August was Sextilis (6), but then Julius Cesar and Emperor Augustus came..

September-October-November-December: 7-8-9-10 And July used to be Quintilis (5) and August was Sextilis (6), but then Julius Cesar and Emperor Augustus came.. and got their own month names.