Key events in the life of King Charles III

WATCH: King Charles meets with Rishi Sunak Wearing a navy blue suit and tie, King Charles met with Prime Minister Rishi Sunak for the first time since his cancer diagnosis.

LONDON — King Charles III has been diagnosed with an unspecified type of cancer. Buckingham Palace says the 75-year-old king has begun outpatient treatment.

Some key dates in Charles' life:

Nov. 14, 1948 -- Charles is born on the royal estate at Sandringham, the first child of Princess Elizabeth and Prince Philip.

Feb. 6, 1952 -- Princess Elizabeth becomes Queen Elizabeth II upon the death of her father, King George VI.

July 1, 1969 -- Charles is formally invested as the Prince of Wales.

July 29, 1981 -- He marries Lady Diana Spencer to become the first royal heir since 1660 to marry an Englishwoman.

June 21, 1982 -- Birth of first son, William Arthur Philip Louis.

Sept. 15, 1984 -- Birth of second son, Harry (Henry Charles Albert David).

June 15, 1992 -- Andrew Morton's book "Diana: Her True Story" says Charles has had a long-term affair with a married woman, Camilla Parker Bowles.

Dec. 9, 1992 -- He separates from Princess Diana.

Aug. 28, 1996 -- Charles and Diana divorce.

Aug. 31, 1997 -- Diana is killed in a Paris automobile crash.

Feb. 10, 2004 -- Charles announces his engagement to marry Camilla Parker Bowles.

April 8, 2005 -- He marries Camilla in a civil ceremony; she takes title of Duchess of Cornwall.

April 29, 2011 -- His son, Prince William, is married to Kate Middleton.

December 2011 -- Charles is hospitalized for treatment for a blocked coronary artery.

June 2013 -- He is admitted to a hospital for an exploratory operation on his abdomen.

July 22, 2013 -- He becomes a grandfather for the first time with the birth of Prince George, William and Kate's oldest child. Two more children -- Charlotte and Louis -- follow for the couple.

May 19, 2018 -- His second son, Harry, marries American actor Meghan Markle.

April 9, 2021 -- Charles' father, Prince Philip, dies at 99.

May 10, 2022 -- Charles stands in for Queen Elizabeth II for the first time during the state opening of Parliament, after she had to pull out of the event, citing mobility problems. The delegation of the role, one of the queen's most important duties, was seen by many as the clearest sign that a transition of the monarchy was underway.

Sept. 8, 2022 -- Charles becomes king upon the death of his mother, Queen Elizabeth II.

May 6, 2023 -- He is crowned alongside Queen Camilla in a ceremony at Westminster Abbey.

March 29, 2023 -- Charles travels to Berlin on his first state visit as king.

Nov. 7, 2023 -- He delivers the King's Speech for the first time at the state opening of Parliament.

Jan. 26, 2024 -- Charles enters a London hospital for a three-day stay for treatment of a benign enlarged prostate.

Feb. 5, 2024 -- Buckingham Palace announces that Charles has cancer and will receive outpatient treatment.