London (CNN)Britain's Queen Elizabeth II has lost the last descendant of her original corgi after 14-year-old Willow was put down at Windsor Castle on Sunday following a battle with cancer, according to UK media reports.
Willow was the last in a long line of royal corgis owned by Britain's longest-serving monarch, reported British newspaper the Daily Mail.
Buckingham Palace declined to comment on the dog's death, telling CNN it was a private matter.
The Queen's fondness for corgis is well known, with Willow and the monarch even appearing beside James Bond actor Daniel Craig for a sketch shown during the 2012 London Olympic opening ceremony.
Queen Elizabeth II has reportedly owned more than 30 corgis during her reign.
While the Queen still reportedly owns several other dogs, Willow was the only remaining descendant of Susan, the original corgi given to then-Princess Elizabeth on her 18th birthday in 1944.
She received Susan as a gift after becoming attached to her father King George VI's corgi called Dookie, the Daily Mail reported.
Since then, she has owned dozens of the breed, known for its distinctive short legs and standing-up ears.
Such was Queen Elilzabeth's attachment to Susan, she reportedly took the dog on honeymoon with Prince Philip in 1947.
The royal couple have also owned "dorgies" -- a cross between a dachshund and a corgi.