WINDSOR, England — Royal insiders and historians nodded their heads knowingly when the venue Prince Harry and Meghan Markle's May 19 wedding was announced. After all, the fairy tale-like Windsor Castle is said to be Queen Elizabeth II's favorite home.

But it is much more than that, according to David Lewis, a historian who has lived in the town of Windsor for 30 years.

“It’s history. It’s legitimacy,” he said as he took a break from walking his dog near the gates of the castle on a recent morning. “Right back to the earliest kings, they met at this place.”

Windsor Castle, considered a masterpiece of late Gothic architecture. Christopher Furlong / Getty Images

The imposing fortress and longest-occupied European palace some 25 miles west of London has been the home of British sovereigns for over 900 years.

The castle's grand spaces are lined with masterpieces by artists like Rubens and Rembrandt, portraits of past kings and queens, crystal chandeliers, gold ceiling moldings and knights in armor standing guard. It is still used for important ceremonial events and state visits.

The castle has an added significance for the royal family, which adopted its name in 1917 when it became the House of Windsor.

The name change came during World War I when the royal family’s Germanic name, Saxe-Coburg-Gotha, fell out of favor. The German air raids over London — with bombers dubbed “Gothas” — were the final straw and King George V issued a proclamation declaring that the family would henceforth be known as the House of Windsor.

Queen Elizabeth has spent time in the castle since she was a child, and during World War II she and her sister, Princess Margaret, were evacuated to escape the Nazi bombing of London. According to royal experts, the queen prefers the country retreat to her palace in the capital.

“Buckingham Palace is the office ... Windsor is her home,” said Amanda Bryett, Director of Windsor Tourist Guides. "This is where she grew up."

The queen spends weekends in Windsor from October until July, when she goes to Scotland's Balmoral Castle. The royal standard flies when the queen is in residence, letting everyone knows she’s home.

“This is really where she can relax,” said Bryett, who has lived in Windsor since the 1980s and said she often sees the queen driving her green Jaguar through Windsor's park on her way to church.

King George VI and Queen Elizabeth with Princesses Margaret, left, and Elizabeth at the Welsh House, a miniature cottage in the grounds of Windsor Castle, in 1931. Lisa Sheridan / Getty Images

“She goes horse riding in the park, she walks her dogs in the park,” said Bryett marveling at the fact that, at 92, the monarch is still so active. “She was out last week.”

Even though she lived through the war there, the queen was reportedly surprised to learn, when it was revealed to her during a BBC documentary this year, that the crown jewels had actually been hidden in a cookie jar at the castle during World War II.

Windsor Castle really is “her majesty the queen's favorite home,” said Andrew Roberts, a British historian and royal commentator for NBC News. “So it's very fitting that Meghan and Harry should have chosen somewhere that matters so much to his grandmother to have their wedding.”

The actual ceremony will take place in St. George’s Chapel. King Edward IV set in motion the building of the chapel in 1475 and it was completed 50 years later by King Henry VIII.

With its fan-vaulted ceiling and stained glass windows, it is considered a masterpiece of late Gothic architecture. It is also the chapel of the Order of the Garter, Britain’s most prestigious order of chivalry.

The intimate choir area is lined with colorful banners, with heraldic family crests, symbols and animals, hanging above the area where the couple will exchange vows.

The chapel is also the burial place of King Charles I, King Henry VIII and King George III — who was forced to give up Britain's American colonies in 1783 after the Revolutionary War.

“There's something of an irony, of course, in that King George III is buried only a few yards away from where Meghan is going to be taking her vows,” said Roberts. “And so the last king of America is actually going to see an American joining his family.”

After the wedding ceremony, the couple will take a carriage procession through the town of Windsor, which is expected to be jammed with 100,000 spectators. Millions more are expected to follow on TV and online, with as many as 79 international broadcasters covering the event, according to royal officials.

The carriage procession will pass by Frogmore House, where Prince Charles will host a private reception for 200 guests the night of the wedding, and return to the castle along the tree-lined Long Walk.

Frogmore itself has American as well as royal connections. The Duke and Duchess of Windsor, whose relationship changed the course of the British monarchy, are buried on the grounds. The Duke — the former King Edward the VIII — abdicated in 1936 to marry American divorcee Wallis Simpson, who later became the duchess; his younger brother, the current queen's father, became King George VI.

Princesses Elizabeth, right, and Princess Margaret sunbathing outside Windsor Castle in 1941. Lisa Sheridan / Getty Images file

Windsor’s 30,000 residents are bracing themselves for their day in the spotlight.

“I think people can see that Harry is besotted — so happy. And we are just thrilled they’ve chosen Windsor,” Bryett said, adding that the town expects a bump in tourism for years to come.

The Rev. Ainsley Swift has called Windsor home for the last 20 years as a Church of England rector. He’s not involved in the royal wedding ceremony, but since Windsor Parish Church, one of the churches he oversees is on street where Harry and Meghan’s horse-drawn carriage procession will pass, he’s one of many getting ready.

“The town has both of a spring in its step and a sense of, ‘Oh my goodness,’” Swift said. “This is bigger than any of us.”