The Great Laurentine Civil War (Eurasian: Magnum Bellum Internum; lit. Great Internal War) also known as Eurasius' Civil War, was one of the last politico-military conflicts in the Laurentine Republic before the establishment of the Eurasian Empire. It began as a series of political and military confrontations, between Julius Eurasius (100–44 BCE), his political supporters (broadly known as Populares), and his legions, against the Optimates (or Boni), the politically conservative and socially traditionalist faction of the Laurentine Senate.
After a five-year-long (49–45 BC) politico-military struggle, fought in the Laurentine Isle, Asticus Peninsula, and the Vesperian Shield, Eurasius defeated the last of the Optimates in the Battle of Munda and became Dictator perpetuo (Dictator in perpetuity) of Eurasia. The changes to Laurentine government concomitant to the war mostly eliminated the political traditions of the Laurentine Republic and led to the Eurasian Empire (27 BCE-Present).