1. Balerion. Balerion the Black Dread is the largest dragon in Westeros' history, having been born in Old Valyria. His shadow is said to blot out a whole town and he could apparently swallow a mammoth whole.
Balerion was the greatest Targaryen dragon who ever lived, the largest since the fall of Valyria. Dragons keep growing for their entire lives, meaning that Balerion was even larger during the Faith Militant uprising. Only Vhagar ever managed to approach Balerion in size, but only many years after his death.
Vhagar is the largest dragon.
Vhagar is the oldest dragon of the ones owned by House Targaryen in "House of the Dragon," and was previously ridden by Visenya Targaryen during King Aegon I Targaryen's reign years before the series picks up.
The process behind arriving on that rather astute observation, and then building up another equally astute conclusion about the relative sizes of their bodies, clearly revealing Balerion is still at least twice as large as Drogon.
Balerion - Ridden by Aegon the Conqueror
Named after an ancient god of the Valyrian Freehold, Balerion was born in Valyria and was one of the dragons that Aenar Targaryen brought with him when he fled to Peyredragon to survive the Doom of Valyria. He was ultimately the last dragon to see the Freehold at its peak.
Drogon is believed to be the reincarnation of Balerion the Black Dread, but Daenerys decides to give him a new name for his new life. The largest and most aggressive of Daenerys's three dragons, Daenerys has problems reining him in.
No, Drogon was smaller than Vhagar.
In a behind-the-scenes video on the official Game of Thrones YouTube channel, visual effects Producer Nikeah Forde explained that Vhagar is 150 meters long. Drogon, by comparison, is estimated to be between 50-60 metres long.
With the biggest of them all, Balerion, The Black Dread, already deceased, the two other biggest dragons still alive in Westeros are Vhagar and Vermithor, the first claimed by Aemond Targaryen and the second yet to be claimed.
Vhagar, almost two centuries old and the strongest dragon alive, took a fatal bite out of Arrax, killing him and his young rider Prince Lucerys "Luke" Velaryon (Elliot Grihault).
During the Dance of the Dragons, Vhagar was said to rival Balerion in size, but it seems like the Black Dread was still slightly bigger.
The WOIAF makes it clear: Balerion was, easily, 50 time bigger than Drogon.
Aegon I is the pinnacle of Targaryen greatness. His name is mentioned so often across the course of the show that book-averters and die-hard fans alike can both recite his history. He is the reason that the Seven Kingdoms exist as we know them. He is the legendary rider of the largest dragon, Balerion the Black Dread.
Balerion, also known as Balerion the Black Dread, was one of the three dragons belonging to House Targaryen prior to the War of Conquest and was named after one of the old gods of Valyria. Balerion was ridden by Aegon the Conqueror during the War of Conquest.
The moment happens in season 3, episode 4, “And Now His Watch Is Ended,” when Joffrey Lannister is chilling with Margaery Tyrell and giddily explains, “Rhaenyra Targaryen was murdered by her brother, or rather, his dragon. It ate her while her son watched. What's left of her is buried in the crypts right down there.”
No. Drogon is said to be the largest dragon even before they reach Meereen. It's debatable whether or not being locked up affects their growth. We're told the Targaryen dragons never surpassed Balerion, but no Targaryen dragon lived to be as old as Balerion, and dragons never stop growing.
Vhagar has proven to be very powerful in House of the Dragon, but the formidable Vermithor rivals her. In House of the Dragon season 1, episode 10, Vhagar's strength and size are shown in her easy defeat of Prince Lucerys and Arrax.
As we know, Vhagar is the last surviving dragon of Aegon the Conqueror's Conquest of Westeros. She was ridden by Visenya Targaryen, and, after her first rider's death, she spent 29 years by herself, with no one mounting her.
Laena died early in 120 AC. It is said that Laena attempted to reach Vhagar in her final hour as to fly one last time, but she did not have the strength. Following Laena's funeral on Driftmark, the ten-year old prince Aemond Targaryen claimed Vhagar as his own dragon.
Meraxes was a great dragon that lived during the War of Conquest and reign of Aegon I Targaryen, the first king of the Seven Kingdoms. He was the middle dragon, smaller than Balerion, but bigger than Vhagar. Its scales were silver, and his eyes golden.
Before he died of old age in 94 AC (After Conquest), Balerion was known throughout the Seven Kingdoms as the most terrifying creature alive, and he was no doubt the most fearsome asset to House Targaryen's rule.
Balerion was owned by House Targaryen and was passed down through the family. Owners included Aegon I Targaryen, Maegor I Targaryen, Aerea Targaryen and in House of the Dragon, he is owned by (the soon-to-be King) Viserys I Targaryen (Paddy Considine).
As we all know, Daenerys received her three dragon eggs as a wedding gift from Illyrio Mopatis. They later hatched, birthing the dragons Rhaegal, Viserion and Drogon.
Drogon, the left, black dragon egg. Daenerys is given three dragons eggs by Magister Illyrio Mopatis on the occasion of her wedding to Khal Drogo. She is drawn to these eggs and always keeps them in a chest with her. Viserys tries to steal them but is stopped by Ser Jorah Mormont.
For the Targaryen prince sometimes known as "the last dragon", see Rhaegar Targaryen. The last dragon belonging to House Targaryen died young in 153 AC, during the later part of the reign of King Aegon III, who was called the Dragonbane.