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"You see the numerals around the edge of the coins? On real Galleons that’s just a serial number referring to the goblin who cast the coin. On these fake coins, though, the numbers will change to reflect the time and date of the next meeting. The coins will grow hot when the date changes, so if you’re carrying them in a pocket you’ll be able to feel them. We take one each, and when Harry sets the date of the next meeting he’ll change the numbers on his coin, and because I’ve put a Protean Charm on them, they’ll all change to mimic his."
— Hermione Granger explaining the Protean Charm and the D.A. coins[src]

The Protean Charm (incantation unknown) was a charm that allowed several objects to change simultaneously through a common purpose.[1]

It was considered advanced N.E.W.T.-level magic, all members of Dumbledore’s Army were impressed when Hermione Granger revealed that she could cast this spell.[2]


In 1995, Hermione Granger used this charm to link fake coins in order to communicate with the members of Dumbledore's Army.

A change in one fake Galleon (in this case, a master coin) would be magically reflected in the others so that when Harry transfigured his coin to show a new date for a D.A. meeting the transfigurative change would be carried over to all the others. This change would also emit heat as a signal that they were being changed by the charm to conform with Harry's.

The members would, therefore, be alerted to any "announcement" of a new date for another D.A. meeting. Ravenclaw Terry Boot commented that the charm was N.E.W.T.-level and was very impressed by her ability to perform it as a fifth year.[1]

Second Wizarding War

The coins were used constantly by various D.A. members until 1996. At that time, Ron Weasley and Hermione attempted to summon help during the Battle of the Astronomy Tower, but only Neville Longbottom and Luna Lovegood responded, as they were especially vigilant members.[3]

The Protean-charmed Galleons were used once again in 1998 when the D.A. convened in the Room of Requirement to form a resistance against Headmaster Severus Snape and the Carrow professors.[4]

Draco Malfoy, inspired by Hermione's coins, used a similar method to communicate with Madam Rosmerta, whom he had under the Imperius Curse as part of his plan to assassinate Albus Dumbledore.[5]

Known practitioners

Terry Boot: "You can do a Protean Charm?"
Hermione Granger: "Yes."
Terry Boot: "But that's... that's N.E.W.T. standard, that is."
— Hermione's ability to perform N.E.W.T.-level magic[src]


The English word Protean derives from Proteus, a god in Greek mythology. Proteus was a shape-shifter, able to take many forms. As a result, the word Protean has come to refer to versatility, flexibility, or an ability to assume many forms. "Protean" is also similar to "protein", derived from the same root, meaning a variable, flexible substance which forms strong bonds between its constituent parts.

Behind the scenes

  • It is speculated that when Lord Voldemort branded Death Eaters with the Dark Mark, he used the Protean Charm. Though this is not for certain, it is supported by the fact that when a Death Eater touches his or her mark, the marks on other Death Eaters begin to burn in a way similar to that of the coins used by Dumbledore's Army and darken (the D.A. coins also change in appearance, though through engravings, not colour, when activated).


Notes and references

  1. 1.0 1.1 1.2 1.3 1.4 Harry Potter and the Order of the Phoenix, Chapter 16 (In The Hog's Head)
  2. Harry Potter and the Order of the Phoenix, Chapter 19 (The Lion and the Serpent)
  3. Harry Potter and the Half-Blood Prince, Chapter 29 (The Phoenix Lament)
  4. Harry Potter and the Deathly Hallows, Chapter 29 (The Lost Diadem)
  5. 5.0 5.1 Harry Potter and the Half-Blood Prince, Chapter 27 (The Lightning-Struck Tower)