No Mediterranean Sea

In 108 AD in the 10th year of the Roman Emperor Trajan a series of 6 massive earthquakes measuring between 5.2 and 8.3 on the MMS scale occur in the area of ocean west of the straits of Gibraltar on the Azores-Gibraltar Transform Fault. The sea bed in the surrounding area begins to raise from roughly 350 metres deep to less than 50 metres deep.

The earthquakes cause several large Tsunamis that strike the western coast of the Roman provinces of Hispania and Africa Proconsularis causing major damage and causing the deaths of many thousands.

In 309 AD under the reign of the Roman Emperor Consintine another four major earthquakes occur on the Azores-Gibraltar Transform Fault, these earthquakes cause the staights of Gibraltar (or the Pillers of Hercules as it was known then) to become 4 metres above sea level. This causes the Mediterranean Sea to be cut off from the Atlantic ocean.