"Grindelwald. You cannot imagine how his ideas caught me, Harry, inflamed me. Muggles forced into subservience. We wizards triumphant. Grindelwald and I, the glorious young leaders of the revolution. Oh, I had a few scruples. I assuaged my conscience with empty words. It would all be for the greater good, and any harm done would be repaid a hundredfold in benefits for wizards. Did I know, in my heart of hearts, what Gellert Grindelwald was? I think I did, but I closed my eyes. If the plans we were making came to fruition, all my dreams would come true."
-- Albus Dumbledore (DH35)
Grindelwald was a brilliant student at Durmstrang Institute, but was expelled in 1899 at the age of 16, at which point he chose to go abroad for a few months, moving in with his great-aunt Bathilda Bagshot in Godric’s Hollow (DH18) because he was fascinated by the legend of the Deathly Hallows and wanted to explore the place where Ignotus Peverell had died and was buried (DH35). During his stay in Godric’s Hollow, Gellert became very close with then 18-year-old Albus Dumbledore, and drew the latter into his plans for world domination. Together they theorized about Wizard supremacy “For the Greater Good” of the world, and how to find the three Deathly Hallows: The Elder Wand, the Cloak of Invisibility, and the Resurrection Stone. However, their relationship lasted mere months; Grindelwald fled when Albus’s unstable sister Ariana was killed during a quarrel, and Dumbledore realized his folly (DH18, DH28).
During his subsequent rise to power as a Dark wizard, Gellert built a prison, Nurmengard, to hold his opponents, over the door of which the slogan “For the Greater Good” was carved (DH18). Although he was well aware of Grindelwald’s abuses of power and evil actions, Dumbledore avoided having to confront his former friend because he was afraid Grindelwald would tell him who it was that had cast the spell that killed Ariana — and Dumbledore was terrified that it might have been him. However, Dumbledore eventually had to try to stop Grindelwald, even at great personal cost.
The spectacular final battle between Dumbledore and Grindelwald took place in 1945, the final year of World War Two, and the year that Voldemort finished Hogwarts. In the end, Dumbledore won the duel and took Grindelwald’s wand, the Elder Wand of Deathly Hallows fame. This battle was such a notable event that it is featured on Dumbledore’s Chocolate Frog card as one of the three things Dumbledore is particularly famous for (PS6). Grindelwald was imprisoned in Nurmengard (DH18), where he remained until his murder by Voldemort in 1998 (DH23).
Ancestry: Probably pureblood.
Great-aunt: Bathilda Bagshot, the author of A History of Magic (DH).
Relationships: Albus Dumbledore fell in love with Gellert when Albus was 17, but was “terribly let down by him” when he realized what Gellert was capable of (CH2).
Wand: The Elder Wand, one of the three Deathly Hallows, which he stole from the wandmaker Gregorovitch.
School: Brilliant student at Durmstrang, but expelled c. 1899 (DH18).
Career: Attempted to establish wizard supremacy over Muggles, but was defeated and imprisoned for the rest of his life.
Incarceration: From 1945-1998 at Nurmengard, prison he had built for his own political enemies (DH18).
Bathilda Bagshot was his Great Aunt.
First name meaning: A possible source for the name has been suggested by Lexicon reader Olive Campion:
When I was younger I read a terribly sad story called 'Hound Gelert' (it is spelled with one 'l' in this case), which I remembered all my life. It is an aetiological story, as in it explains the name of a place. It's about a legendary Welsh prince called Llywelyn who had a hunting dog called Gelert, with whom he was best friends and whom he took everywhere. You can read it here: http://www.valleystream.co.uk/gelert.htm. That is essentially how I remember it, only in the version I read, Llywelyn already had Gelert as a hunting dog before he got married, and he deliberately left Gelert to look after the baby because he trusted Gelert more than anyone else, and he then returned home to find the scene as described.
I know Grindelwald the wizard isn't much like a faithful hound in character, but Llywelyn's situation had aspects that reminded me of Dumbledore: having to attack - in this story, kill - his best friend; perceived betrayal; blame/guilt for the death of a family member - although in the Hound Gelert story the family member wasn't dead; and never being truly happy again after that.
It is also possible that the name refers to Bishop Gellért of Budapest (980-1046) who was martyred in a pagan Magyar revolt against Christianity. A hill, cave and four-star hotel in Budapest are named for him.
Last name meaning: 'Grindelwald' is a small village in the Alps of Switzerland. The name could also refer to Grendel, the troll-like monster of the Anglo-Saxon epic Beowulf. Jo pronounces Grindelwald's name “GRIN dell vald” (TLC pt. 3).
Grindelwald's fate in Deathly Hallows directly contradicts a statement by J.K. Rowling in 2005 that Grindelwald died in 1945 (TLC pt. 3).
I'm going to tell you as much as I told someone earlier who asked me. You know Owen who won the [UK television] competition to interview me? He asked about Grindelwald [pronounced "Grindelvald" HMM…]. He said, “Is it coincidence that he died in 1945,” and I said no. It amuses me to make allusions to things that were happening in the Muggle world, so my feeling would be that while there's a global Muggle war going on, there's also a global wizarding war going on.
From the Web
Scribbulus Issue 1, March 2006: Harry Potter and the Third Reich by: WaggaWaggaWerewolf