King Charles III was officially announced as Britain’s monarch on Saturday as the mourning period for Queen Elizabeth’s passing began. Senior MPs, including Prime Minister Liz Truss, swore a new oath of allegiance to King Charles, while the date for Her Majesty’s funeral was also announced.

Charles also addressed the nation for the first time on Saturday, in an emotional speech where he spoke dearly about his mother. Yet as he takes the throne, certain phots are leaving royal fans concerned about the state of his health.

Her Majesty, Queen Elizabeth, passed away on Thursday at her summer residence of Balmoral in Scotland. Her reign saw 15 different prime ministers, from Winston Churchill to the newly-appointed Liz Truss. The Queen will be remembered as one of, if not the most, iconic figures in British history.

“The Queen died peacefully at Balmoral this afternoon,” Buckingham Palace said in a statement Thursday.

The flag atop Buckingham Palace was lowered to half-mast at 6:30 p.m. local time, while an official notice announcing the Queen’s death was posted on the gates to the palace, as is tradition. Her Majesty has since been honored worldwide, not least in Britain.

On Friday, gun salutes took place in London and around the UK in tribute to Queen Elizabeth. One round was fired every 10 seconds, 96 times, one to represent each year of the monarch’s life.

Queen Elizabeth left Balmoral for the last time on Sunday – in an oak coffin draped in the Royal Standard of Scotland, adorned with a big bouquet – as the hearse left the royal estate. The journey from Balmoral is the first in several events leading up to the funeral in Westminster Abbey on September 19.

On Sunday – after a six-hour drive through the Scottish Highlands, which saw thousands of mourners line the roads – the Queen’s coffin arrived in Edinburgh.

Soldiers wore kilts while bearing the coffin to the throne room at the Palace of Holyroodhouse, Her Majesty’s official Scottish Residence. She will then lie in state at Edinburgh’s St Giles’ Cathedral, where the public can pay their respects.

On Monday, King Charles will fly to Edinburgh to join his sister Princess Anne and brothers, Princes Andrew and Edward, as the coffin of Queen Elizabeth is taken from one of her Scottish palaces to St. Giles Cathedral. Her coffin will be flown to London on Tuesday,

Queen Elizabeth’s funeral will reportedly be held Monday, September 19, in Westminster Abbey. Her Majesty will then be taken to St George’s Chapel at Windsor Castle, where she will be buried with her husband, Prince Philip.

The Queen’s eldest son, Charles – the former Prince of Wales – has now become King of the United Kingdom and the 14 Commonwealth realms.

On Saturday – in an emotional first address to the nation – the newly announced 73-year-old king spoke highly about his beloved mother.

“Her dedication and devotion as Sovereign never waivered, through times of change and progress, through times of joy and celebration, and through times of sadness and loss,” King Charles III said, adding a few heartfelt words for his wife of 17 years, Camilla, who becomes Queen Consort.

“I know she will bring to the demands of her new role the steadfast devotion to duty on which I have come to rely so much.”