A family dinner and low-key public engagements marked the Queen’s birthday in April, but the United Kingdom is gearing up for a much larger and more public birthday celebration later this week.

Despite being born on April 21, 1926, the Queen has celebrated two birthdays a year ever since she took the throne.

The tradition of celebrating a monarch's birthday dates back to the mid-18th century with King George II.

If a monarch's birthday didn't happen to be in the summer months, then they were given two birthdays – a tradition that has endured.

"[The U.K.] now marks it on a day that makes sense for tourism and weather," CTV's Royal Commentator Richard Berthelsen said in an interview with CTVNews.ca.

The idea to have two birthdays change came out of a desire for warm weather to celebrate the Trooping the Colour – a military procession where armed forces regiments would march and display their crests.

May and June were chosen as having the best chance of good weather.

In 1974, Queen Elizabeth II marked the second Saturday in June as her public birthday in the United Kingdom.

Having a second birthday also allows a chance for the public to celebrate, Berthelsen says.

"The major life events of a monarch in a constitutional monarchy don't just exist for them. They belong to everyone," he said, "All those moments in her life belong to the people and it's a chance to reflect back on the Queen and on our country and its history."

While the timing of celebrations may have become restricted within Britain, it varies across the Commonwealth.

The Falklands celebrate her birthday on April 21 – her legal birthday – while in Australia, different states celebrate on different days.

Few Canadians may realize it but Victoria Day long weekend is technically the "proper" time to celebrate Queen Elizabeth II's birthday.

"Really, legally, what we're celebrating is the Queen's birthday. We just still call it Victoria Day," said Berthelsen.

The decision to establish Victoria Day and Queen Elizabeth II's came via a royal proclamation in 1957, following several years of yearly proclamations specifying when to celebrate her birthday following her coronation in 1952.

Even monarchists believe the dates can cause confusion in Canada.

"I think that a lot of Canadians are confused by it. It's confusing. It's called Victoria Day, it's not called 'the Queen's birthday' or 'Elizabeth Day'," said Robert Finch, the chair of the Monarchist League of Canada.

However, Finch argues that celebrating it at a different time than the United Kingdom keeps the celebration unique for Canadians.

He says it serves to recognize both a central figure in Canadian history – the former Queen Victoria – and Queen Elizabeth II.

"It's the one day in the year where Canadians are reminded they live in a constitutional monarchy and we have a queen as the head of state. It's a day to celebrate our democracy, our parliamentary traditions, the Westminster system of government and all those core features of Canada we have thanks largely to the Crown," he said.

This year, Niagara Falls and the CN Tower were lit up purple and violet as a show of recognition for the monarchy.

A new silver coin designed by the Royal Mint was also unveiled at a party hosted by the Monarchist League of Canada to help celebrate the Queen's birthday.

Mint unveils coin celebrating Queen's birthday

This year, the Queen marked her legal birthday by walking and meeting well-wishers outside Windsor Castle, followed by lighting a ceremonial beacon and unveiling a walkway in Windsor that marks 63 significant parts of the town.

She capped off the day with a dinner with family members.

Queen Elizabeth II celebrates her 90th birthday

Further birthday celebrations were held from May 12 to 15, with a festival held on the grounds of Windsor Castle.

Members of the RCMP Musical Ride took part, forming an honour guard to meet her when she arrived for the festivities and as part of a gala that included 900 horses and 1,500 performers.

The monarchy has a series of private and public festivities planned to mark the June public celebrations.

The Queen will attend a service of thanksgiving at St. Paul's Cathedral on June 10, which also happens to be Prince Philip's birthday.

On Saturday, June 11, she'll watch the Queen's Birthday Parade – which includes the Trooping the Colour – with other members of the Royal family before appearing on the balcony of Buckingham Palace to watch fighter jets take part in a fly-over.

The weekend of birthday activities will end with a street party on the road leading to Buckingham Palace, with a picnic and street performances held for organizations and charities the Queen supports.