“A crown of thorns... a purple robe”
The soldiers twisted together a crown of thorns, set it on His head, and dressed Him in a purple robe. And they went up to Him again and again, saying, 'Hail, King of the Jews!' and slapping Him in the face. (John 19:2–5 BSB)
What it sounds like today
Random cruelty with props.
The cultural key
Not random but a complete mock coronation, item for item: the soldier's scarlet cloak stands in for royal purple; the plaited thorns for a ruler's wreath or radiate crown; the reed for the scepter; the kneeling and 'Hail, King of the Jews!' parody the 'Ave Caesar' acclamation. A whole cohort stages the investiture of a client king, as barracks theater. Games mocking condemned prisoners as kings are attested in the period. John, like Mark, has the royal purple. And he alone extends the scene: Pilate brings Jesus out still wearing the crown and robe and presents him: 'Behold the man!' The barracks joke becomes the official exhibit, and John's irony peaks: the governor displays the true king in coronation costume to the crowd that will shout 'we have no king but Caesar.'
Recovered meaning
Matthew lets the mockery tell the truth the mockers can't see: robe, crown, scepter, homage, royal title: every element of a real coronation is present and, on the Gospel's terms, valid. The soldiers crown the king while laughing at him.