Walk up to the Round Tower today and it feels permanent. Solid. Like it’s been sitting on that chalk hill since the dawn of time. But if you're asking when was Windsor castle built, the answer isn't a single date you can circle on a calendar. It’s more like a thousand-year-long construction project that never actually stopped.
William the Conqueror started the whole thing around 1070.
That’s the "official" beginning. He’d just finished the Norman Conquest and needed a ring of fortifications around London. He chose this specific spot—high above the River Thames and on the edge of a Saxon hunting ground—to keep a watchful eye on the locals. It wasn't a palace then. Far from it. It was a "motte and bailey" castle, basically a big mound of earth with a wooden fence on top. Think of it as a rough military outpost rather than the sprawling, 1,000-room masterpiece we see today.
The Norman Roots and Why 1070 Matters
William didn't build for comfort. He built for survival. By 1086, the Domesday Book already notes the castle’s existence, making it one of the oldest recorded structures in England.
Why there? Strategic genius, honestly. It was a day’s march from the Tower of London. If the city revolted, the King had a fallback. The original wooden walls were functional, but wood rots and burns. It took nearly a century before the kings of England realized they needed something more permanent. Henry II, who took the throne in 1154, is the guy we have to thank for the stone version. He replaced the timber stockade with stone walls and built the first version of the Round Tower.
It’s kind of wild to think that the core layout hasn't changed much in 900 years. The Upper Ward and Lower Ward divisions we walk through today are the same footprints the Normans laid out.
Henry III and the Gothic Transformation
By the 1200s, the castle started looking less like a fort and more like a home. Henry III was obsessed with luxury. He spent a fortune—seriously, a staggering amount of tax money—on building a lavish royal palace within the walls.
He didn't just stop at bedrooms. He built a huge chapel. This era saw the castle survive a massive siege during the First Barons' War. Because it held up so well, the royals realized it was the safest place in the country. This is when the Western curtain wall got those three massive towers you see from the town today: the Curfew Tower, the Garter Tower, and the Salisbury Tower.
If you look closely at the Curfew Tower, you’re looking at masonry from 1227. It's survived the Black Death, the English Civil War, and the Blitz.
Edward III and the Knightly Upgrade
If William started it and Henry II solidified it, Edward III made it legendary. In the 1300s, he poured about £50,000 into the site. In today’s money? That’s hundreds of millions.
He wanted a place that felt like King Arthur’s Camelot. He founded the Order of the Garter here in 1348, which is still the highest order of chivalry in the UK. To house them, he basically rebuilt the entire Upper Ward. This was the most expensive secular building project of the entire Middle Ages in England.
He shifted the focus. It wasn't just about keeping people out anymore; it was about showing off power. The "Great House" he built became the blueprint for every royal apartment that followed.
The St. George’s Chapel Era
You can’t talk about when was Windsor castle built without mentioning the late 1400s. Edward IV started St. George’s Chapel in 1475. It’s arguably the most beautiful piece of Perpendicular Gothic architecture in existence.
It took fifty years to finish.
Ten monarchs are buried there, including Henry VIII and the late Queen Elizabeth II. When you stand inside, the stone vaulting feels almost weightless. It was a statement of religious and dynastic might. By the time the chapel was finished in the reign of Henry VIII, the castle had transitioned from a medieval fortress into a sprawling, Renaissance-style palace complex.
The George IV Glow-Up
Honestly, the Windsor we see in 2026 looks the way it does because of King George IV. He was... extravagant. In the 1820s, he decided the castle looked a bit too much like a mish-mash of old styles. He hired Jeffry Wyatville to give it a "romantic" makeover.
Wyatville did some major things:
- He raised the height of the Round Tower by 30 feet to make it look more dramatic against the skyline.
- He added machicolations (those overhanging gaps for dropping things on enemies) that weren't actually for defense—they were just for the "vibe."
- He created the Long Walk, that iconic three-mile straight path leading to the castle.
This was the final massive structural change. George IV wanted a "medieval" look, but he built it with 19th-century money and ego. Most of the "old" looking battlements are actually from this period.
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The Fire of 1992 and Modern Reconstruction
History isn't just about the distant past. On November 20, 1992, a fire broke out in the Private Chapel. It gutted the State Apartments and destroyed St. George’s Hall.
This was a pivot point.
Instead of just patching it up, the restoration became a masterclass in traditional craftsmanship. They used the same techniques—hand-carving oak, gilding with real leaf—that were used centuries ago. The restoration was completed in 1997, five years to the day after the fire started. It cost £37 million. It was a reminder that Windsor is a living, breathing entity. It’s constantly being "built."
Debunking the Myths
People often think the castle was built all at once. It wasn't. It’s a Frankenstein’s monster of architecture.
Another common mistake? Thinking the Round Tower is actually round. It’s not. It’s an irregular shape that follows the mound it sits on. And despite what some guides say, the "secret" tunnels aren't really that secret—they were mostly service passages and sally ports for soldiers to sneak out and attack besiegers from behind.
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Why the Timing Matters Today
Windsor is the longest-occupied royal palace in Europe. Every era left a fingerprint.
- The Normans: The layout.
- The Plantagenets: The fortifications.
- The Tudors: The gatehouses.
- The Victorians: The uniformity.
If you’re planning to visit, don't just look at the grand rooms. Look at the stones. You can literally see the change in masonry styles as you walk from the Lower Ward to the Upper Ward.
Actionable Tips for Your Visit
- Check the Flag: If the Royal Standard is flying, the King is in residence. If it’s the Union Jack, he’s away. You’ll get access to more areas when he’s not there.
- Timing the Guard: The Change of the Guard usually happens at 11:00 AM, but check the schedule. It’s a military tradition that has stayed consistent for centuries.
- The Doll's House: Don't skip Queen Mary’s Dolls' House. It was built in the 1920s and has working plumbing and electricity. It's a tiny time capsule of the era.
- Book Early: Windsor is one of the most visited sites in the world. If you turn up at noon without a ticket, you're going to spend your day in a very long line.
- Look for the "Old" Stone: In the North Terrace, you can find original 12th-century stone work hiding behind the more modern Victorian flourishes.
Windsor wasn't "built" in a year. It was willed into existence over ten centuries by kings and queens who wanted to make sure they were never forgotten. When you walk through those gates, you aren't just entering a building; you're stepping into a timeline that started with a Norman warlord and continues into the present day.