English Reference
Idiom idiom

Et tu, Brute?

C1 Literary Roman origin
Meaning

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

Examples
SIMPLE

“You voted against me too? Et tu, Brute?”

CONTEXTUAL

“When his oldest colleague signed the complaint, he read the list of names twice and muttered, "Et tu, Brute?"”

COMPLEX

“He had expected opposition from the newer partners and had prepared for it; what he had not prepared for was the Et tu, Brute? moment of finding his mentor's signature at the bottom of the page.”

Origin
disputed origin

Marcus Junius Brutus owed Caesar a great deal. Caesar had pardoned him after he fought on the losing side of the civil war, promoted him, and was rumoured — probably wrongly — to be his father. Brutus was among the men with knives in the Senate on 15 March 44 BC.

Ancient accounts disagree about what Caesar said. Suetonius reports that he died without a word, though he adds that some claimed he spoke to Brutus in Greek: kai su, teknon — you too, child. The Latin Et tu, Brute? is not from any Roman source at all. It was already circulating on the Elizabethan stage when Shakespeare gave it to Caesar in 1599, and it is Shakespeare's version that stuck.

In English the phrase is used, usually with a note of theatre, at the moment a friend or ally turns out to have joined the other side.

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

    beware the Ides of March (idiom)

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

    Spurinna's warning, 15 March 44 BC.
  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