English Reference
Idiom idiom

beware the Ides of March


A warning that a specific day, or a trusted circle, holds danger.


SIMPLE

The results come out on the fifteenth — beware the Ides of March.

CONTEXTUAL

Every year the accountant tells his clients to beware the Ides of March, because that is when the first tax deadline falls.

COMPLEX

The columnist warned the prime minister to beware the Ides of March, noting that every serious challenge to her leadership had come not from the opposition benches but from the people sitting directly behind her.


The Romans did not number the days of a month forward the way we do. They counted back from three fixed points, and the Ides was the middle one — the 15th in March, May, July and October, the 13th in every other month. On its own the Ides of March was just a date, and a cheerful one: a festival day.

Plutarch records that a seer named Spurinna warned Caesar that danger would come to him no later than the Ides of March. On the day itself Caesar is said to have passed the man on his way to the Senate and remarked that the Ides had come; Spurinna answered that they had come, but not gone. Caesar was killed in that meeting, on 15 March 44 BC.

Shakespeare compressed the whole exchange into three words — "Beware the ides of March" — and that is the form English kept. It now serves as a warning about a marked day, or about people close enough to be trusted and near enough to do harm.

Caesar & the Republicconnected storiesSee all Roman origin →

One general, one river, and the end of the Republic.

  1. 01

    cross the Rubicon (idiom)

    To take a step you cannot undo.

    The Rubicon, January 49 BC.

  2. 02

    the die is cast (idiom)

    The decision is made and there is no going back.

    What he said at the crossing.

  3. 03

    veni, vidi, vici (idiom)

    I came, I saw, I conquered — used of a job done fast and without difficulty.

    Zela, 47 BC — the war report.

  4. 04

    Caesar's wife must be above suspicion (idiom)

    People in public positions must avoid even the appearance of wrongdoing, guilty or not.

    The Bona Dea scandal, 62 BC.

  5. 05

    Et tu, Brute? (idiom)

    Said when the person betraying you is the last one you expected.

    Brutus, in the Senate.

  6. 06

    sic semper tyrannis (idiom)

    Thus always to tyrants — a slogan claiming that oppressors get what is coming to them.

    What the assassins told themselves.

Last updated August 3, 2026