When any senior member of the British royal family dies it is a significant occasion for the nation and the Commonwealth, and the death of the Duke of Edinburgh will be no exception.
As the royal consort, he is entitled to a full state funeral at Westminster Abbey in London, as well as a period of time lying in state.
However, Prince Philip's own wishes for a "no-fuss" send-off will mean the commemorations for the 99-year-old are curtailed significantly.
And COVID-19 restrictions still in place in the UK could mean some events may not happen at all.
Prince Philip will be mourned officially
Just as it will when the Queen dies, the United Kingdom has already entered a state of national mourning.
This will last until the duke's funeral, which itself may be brought forward due to COVID-19.
The bells at Westminster Abbey rang out 99 times over the course of two hours on Friday (local time) in Prince Philip's memory.
Flags around the country have been lowered to half mast at government buildings and military facilities, with a focus on naval flags, given Prince Philip's close ties with the Royal Navy.
One flag that will not fly at half-mast is the Royal Standard, which is flown when the Queen is in residence in one of the royal palaces.
That flag represents the monarchy and is never lowered.
Members of parliament are now required to wear black armbands on their left arm, and male MPs will have to wear black ties, while the ceremonial mace that sits in the House of Commons was due to be draped in black or have a black bow fastened to it.
How these rules will be adhered to with the current partially virtual parliament remains unclear.
Councils across the UK will scale back official business through the period of mourning.
The Queen herself has now entered a period of mourning that will last for up to eight days. She will not conduct any affairs of state, and laws will not be given royal assent.
The official period of royal mourning can be 30 days, after which the Queen will return to her former duties.
On Saturday at 12:00pm (local time), a "Death Gun Salute" will be fired to mark Prince Philip's death.
"Across the UK, in Gibraltar and on Her Majesty's Ships at sea, 41 rounds will be fired at one round every minute for 40 minutes," the official UK royal website said.
"In London, The King's Troop Royal Horse Artillery will use the same guns that were fired for Her Majesty The Queen and The Duke of Edinburgh's Wedding in 1947, and at The Queen's Coronation in 1953."
In Australia, there will also be a 41 gun salute later today in Canberra, Prime Minister Scott Morrison announced this morning.
The royal family has asked anyone wanting to share their condolences to do so "in the safest way possible" and not to gather at royal residences in the UK.
They have encouraged anyone who wants to send a message to the royal family to do so using the Book of Condolence on its website.
And they have asked anyone who wants to leave floral tributes to instead make a donation to a charity or one of Prince Philip's patronages.
The Duke of Edinburgh will not lie in state
Westminster Hall in the Houses of Parliament is reportedly always ready to host a lying in state, an honour given to the sovereign, the current or past consort, and, occasionally, former prime ministers.
It allows the public to view the coffin and pay their respects to the deceased before the funeral service.
The last time it happened was for the death of Queen Elizabeth, the Queen Mother, in March 2002.
But Prince Philip declined the option and his body will lie at rest in Windsor Castle, where he died, ahead of his funeral.
Prince Philip will not have a State Funeral
As consort, Prince Philip could have a State Funeral at Westminster Abbey, which would include a military procession and a gun carriage drawn by the Royal Navy.
But the College of Arms has confirmed the funeral will be a much smaller ceremony at St George's Chapel in Windsor Castle — the same venue where his grandson Prince Harry married Meghan Markle in 2018 — in accordance with the prince's "no-fuss" wishes.
Having served in the Royal Navy, Prince Philip would have also been in line to receive a military funeral, but due to COVID-19 it will be toned down and feature a guest list of only 30 people — meaning mainly other members of the royal family, and potentially some heads of state from Commonwealth countries.
Buckingham Palace has yet to confirm when it will be held, but traditionally, the funeral would not take place on a Sunday or bank holiday.
However, again, due to COVID-19 this could also change.
Prince Philip's burial
It is expected Prince Philip will be buried at the Royal Burial Ground, a cemetery used for members of the royal family on Frogmore Estate, which is part of Windsor Home Park and not far from Windsor Castle.
Edward VIII, who abdicated in 1936, is buried there, and the burial ground surrounds the Royal Mausoleum, which houses the tomb of Queen Victoria and Prince Albert.
Most other consorts to monarchs are buried in Westminster Abbey or St George's Chapel, where the Queen is most likely to lie upon her death.
