where did the phrase crossing the rubicon come from
This phrase alludes to Julius Caesar's crossing the Rubicon River (between Italy and Gaul) in 49 b.c., thereby starting a war against Pompey and the Roman Senate. Recounted in Plutarch's Lives: Julius Caesar (c. a.d. 110), the crossing gave rise to the figurative English usage by the early 1600s. See also: cross, the.
Origin of RUBICON. Latin Rubicon-, Rubico, river of northern Italy forming part of the boundary between Cisalpine Gaul and Italy whose crossing by Julius Caesar in 49 b.c. was regarded by the Senate as an act of war. First Known Use: 1626.