Cross the Rubicon

Meaning of Idiom ‘Cross the Rubicon’

To cross the Rubicon means to do something which inevitably forces you to follow a certain course of action; a final important decision or event which causes things to change permanently. 1Kirkpatrick, Elizabeth M. The Wordsworth Dictionary of Idioms. Ware: Wordsworth, 1995.,2Ammer, Christine. American Heritage Dictionary of Idioms. Boston: Houghton Mifflin Harcourt, 2013.,3Bengelsdorf, Peter. Idioms in the News – 1,000 Phrases, Real Examples. N.p.: Amz Digital Services, 2012.

Usage

“If things are ever going to change we have to take a bold step. It’s time to cross the Rubicon.”

“The day I signed up for military service I crossed the Rubicon. My entire life was changed from that day forward.”

Caesar Crosses the Rubicon Jacob Abbot, 1849
Caesar Crosses the Rubicon Jacob Abbot, 1849

Origin

The origin of the idiom ‘cross the Rubicon’ is Julius Caesar’s crossing of the Rubicon River in 49 B.C. The river was the border between Cisalpine Gaul and Italy and armies led by generals were forbidden to cross it by law. Caesar’s crossing of this border basically declared war on the Roman Senate and lead to a civil war, one of the last conflicts of the Republic, thus helping to usher in the Roman Empire. This fateful crossing gave origin to the present English idiom by the early 1600’s.

According to Suetonius, upon crossing the river, Caesar said lacta alea est, meaning “the die has been thrown.” This is thought to have lead to the modern English idiom the die is cast. 4 Kirkpatrick, Elizabeth M. The Wordsworth Dictionary of Idioms. Ware: Wordsworth, 1995.,5Ammer, Christine. American Heritage Dictionary of Idioms. Boston: Houghton Mifflin Harcourt, 2013.,6Ayto, John. Oxford Dictionary of English Idioms. Oxford: Oxford U, 2010.

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Sources   [ + ]

1. Kirkpatrick, Elizabeth M. The Wordsworth Dictionary of Idioms. Ware: Wordsworth, 1995.
2. Ammer, Christine. American Heritage Dictionary of Idioms. Boston: Houghton Mifflin Harcourt, 2013.
3. Bengelsdorf, Peter. Idioms in the News – 1,000 Phrases, Real Examples. N.p.: Amz Digital Services, 2012.
4.  Kirkpatrick, Elizabeth M. The Wordsworth Dictionary of Idioms. Ware: Wordsworth, 1995.
5. Ammer, Christine. American Heritage Dictionary of Idioms. Boston: Houghton Mifflin Harcourt, 2013.
6. Ayto, John. Oxford Dictionary of English Idioms. Oxford: Oxford U, 2010.