Holy Thursday is called Maundy Thursday in English from the old Latin name for the day, “Dies Mandatum,” i.e. “the day of the new commandment”.
Zelený čtvrtek (Green Thursday) is how the Czechs and Moravians refer to Maundy Thursday. One explanation is that in many places, before the thirteenth century, green vestments were used for the Mass that day. Another is that this is a reference to “the Green Ones,” the penitents who, being re-admitted to the Church, wore sprigs of green herbs to express their joy. The “grün” in the German name for the day (“Gründonnerstag”, literally Green Thursday) does not derive from the name of the color but is a corruption of the word “greinen” (weinen, to weep).
On this day of the final evening of the Lord, all bells are rung before they are silenced until White Saturday. The sound of bells, about which it is said that they were cast in Rome, are replaced by children’s rattle and clappers and are rattled morning noon and night in the place of bells, and were even used to drive out Judas.
On Zelený čtvrtek the children must go out very early in the morning and bathe – naked! – in the river. This is supposed to be a cure for laziness. And when they come in, shivering and complaining that they’ve just been made to do something they would be punished for in summer, when they would enjoy it, the rope-like jidášky are eaten. Jidášky are served with honey at breakfast. These breakfast cakes, made to look like rope, suggest the fate of Judas Iscariot, who “went and hanged himself” (Matthew 27:5 NKJV) in remorse after he had identified Jesus to His enemies.
In the evening the village boys used to equip themselves with a wooden rattle (řehtačka), which was specially made for the purpose. They formed a group and walked through the village, rattling their rattles vigorously so the noise could be heard from afar.