The correct chronological order of the time periods would be:
1- The Christian Era, also known as "Common Era," which began with the birth of Christ approximately 2000 years ago.
2- The height of the Roman Empire, which took place in the year 117 of the Common Era.
3- The fall of the Roman Empire, which happened in the year 476 of the Common Era.
4- The medieval period, which began with the fall of the Western Roman Empire and lasted from the 5th to the 15th century.