It's been a year of change for the royal family.

Following the death of Queen Elizabeth II in September, her eldest son officially became King Charles III. His ascension to the throne has prompted several members of the family to take on new roles, including Prince William and Kate Middleton. In fact, the monarch officially confirmed William and Kate's new titles—Prince and Princess of Wales—in a message to the nation on Sept. 9.

"With Catherine beside him, our new Prince and Princess of Wales will, I know, continue to inspire and lead our national conversations," Charles shared at the time, "helping to bring the marginal to the center ground where vital help can be given."

And with the new titles comes more responsibility, especially given that William, 40, is now first in line to the throne, behind his 74-year-old father.

As royal expert Jonathan Sacerdoti previously explained to E! News, "Unlike his father, there probably won't be such a long wait because Charles is already in his 70s, which means that William will be coming to the throne in a much shorter period of time."

"Things will shift a bit," Sacerdoti added of William's position. "I think it's a part of growing up and growing into the role and knowing that his duty is going to increase and his service is likely to increase, and there's no reason to think he won't carry that all out excellently."

However, as Sacerdoti noted, the royal family had already been stepping up in recent years amid Queen Elizabeth's health struggles.

As for Kate—who shares kids Prince George, 9, Princess Charlotte, 7, and Prince Louis, 4, with William—the royal expert told E!, "She's always carried out her role with the family actually very well. She's somebody that is immensely popular with the public. They absolutely love her."

Another family member who's role has been greatly impacted? Prince Edward.

In March, in honor of his brother's 59th birthday, Charles gave Edward the title of Duke of Edinburgh, which was previously held by their late father, Prince Philip. 

Prince Edward's wife, Sophie, was also been named the Duchess of Edinburgh. At the time, the couple said in a statement, "The new Duke and Duchess of Edinburgh are proud to continue Prince Philip's legacy of promoting opportunities for young people of all backgrounds to reach their full potential."

While royal fans await King Charles III's coronation on May 6, get more details on his reign below.

Prime Minister Liz Truss was the first to use the name King Charles III to refer to the new British monarch, saying his name in a televised speech outside her headquarters at 10 Downing Street in London on Sept. 8, hours after Buckingham Palace announced Queen Elizabeth II's passing. She had assumed office just two days prior, and met the queen at her home at Balmoral Castle, Scotland in what marked the late monarch's final public appearance.

Several minutes after she gave her speech, a spokesperson for Clarence House, which represented Charles when he was the Prince of Wales, confirmed the new monarch will be known as King Charles III.

Charles, christened Charles Philip Arthur George by England's archbishop of Canterbury, could have chosen a royal name other than King Charles III, and for years, many people speculated he would choose to use one of his middle names. Because...

The monarch is Britain's first King Charles in more than 300 years. His two predecessors' reigns in the 17th century were marred by scandals.

King Charles I (ruled from 1625 to 1949) and King Charles II of England (1660-1685) were both criticized for dissolving their Parliaments. Charles Sr. remains the only British monarch to be tried and executed for treason, having been accused of instigating England's second civil war.

Upon his death, the monarchy was abolished and his son spent several years in exile. Charles II was appointed king when the monarchy was restored in 1660, after which he was dubbed "The Merry Monarch" for leading what many considered a hedonistic court and for allegedly fathering several children out of wedlock.

With Charles' reign comes a slight tweak to the British de facto national anthem. Its title and lyrics, last amended when Elizabeth ascended the throne, will change from "God Save the Queen" back to "God Save the King." All female pronouns will revert to male. The original song debuted in 1745 and its title and pronouns changed over the years with the changing of the monarchs.

Newly minted coins and printed cash in British currency are set to feature Charles' image, although current ones will remain in circulation until they are gradually replaced, Reuters reported.

"As the first monarch to feature on Bank of England banknotes, the Queen's iconic portraits are synonymous with some of the most important work we do," the Bank of England said in a statement. "Current banknotes featuring the image of Her Majesty The Queen will continue to be legal tender. A further announcement regarding existing Bank of England banknotes will be made once the period of mourning has been observed."

Since Charles II's reign, it has become traditional for the monarch to face in the opposite direction to their predecessor. Therefore, the new king's face on money is expected to now face left, Reuters said.

Meanwhile, the Reserve Bank of Australia announced that its "$5 banknotes featuring the image of Her Majesty The Queen can continue to be used," adding, "They will not be withdrawn and are likely to remain in circulation for years to come."

Charles now takes his mother's place as head of the British Armed Forces, the judiciary and the civil service, and as Supreme Governor of the Church of England, CNN reported, adding that the king is also the Fount of Honour, which means all honors, such as knighthoods, will now be given in his name.

As heir to the throne, Charles was known as a staunch environmentalist and often voiced his concerns about climate change. But as king, his days of advocacy may come to an end. In a 2018 BBC interview, he acknowledged that the responsibilities of his then-current role as Prince of Wales was different from that as a monarch. Asked whether his public campaigning will continue, he said, "No, it won't. I'm not that stupid." 

He expressed similar sentiment, less abrasively, in a pre-recorded, first public address as king on Sept. 9. "My life will of course change as I take up my new responsibilities," Charles said. "It will no longer be possible to give so much of my time and energies to the charities and issues for which I cared so deeply, but I know this important work will go on in the trusted hands of others."