Feb. 6 (UPI) -- Two gun salutes in London marked Queen Elizabeth's 65 years on the throne Monday.
King's Troop Royal Horse Artillery in Green Park fired a 41-gun salute at midday and the Honorable Artillery Company fired a 62-gun salute at the Tower of London at 1 p.m.
Queen Elizabeth, 90, became the first British monarch to reach a sapphire jubilee. She was the longest-reigning monarch in British in September 2015 when she surpassed the record set by her great-great-grandmother, Queen Victoria.
A portrait by British photographer David Bailey, originally taken in 2014, was reissued Monday. The queen is wearing sapphire jewelry given to her by her father, King George VI, as a wedding gift in 1947 -- a necklace with 16 large, oblong sapphires surrounded by diamonds and a matching pair of drop earrings.
The queen will spend the day at Sandringham, her country retreat in eastern England, and no official events are planned, according to a palace spokeswoman.
In a statement, British Prime Minister Theresa May congratulated the queen: "Today's Sapphire Jubilee marks yet another remarkable milestone for our remarkable Queen. I know the nation will join with me today in celebrating and giving thanks for the lifetime of service Her Majesty The Queen has given to our country and to the commonwealth."
Elizabeth became queen on Feb. 6, 1952, when her father died. The princess was 25 years old when she ascended to the throne.
Despite being in her 90s, Queen Elizabeth has made frequent public appearances. She missed attending church over the Christmas and New Year holidays because of a "heavy cold." But she attended a service on Jan. 8.
She and Prince Philip will mark 70 years of marriage in November.