BRUSSELS - Belgium's Queen Fabiola, widow of King Baudouin and queen between 1960 and 1993, died on Friday at the age of 86, the royal palace said.
The Spanish-born queen, who was at the centre of a row last year over royal allowances, had been ill for some time and her breathing never fully recovered from a lung infection in 2009.
"Their majesties the King and Queen and the members of the royal family announce with very great sadness the death of Her Majesty Queen Fabiola this evening at Stuyvenberg Castle in Brussels," a statement from the royal palace of King Philippe said.
In 2013, the queen faced criticism, including from the prime minister, over her plan to pass on an estate in Spain to relatives using a trust to avoid paying tax.
The row led to the government cutting state allowances to the royal family, including those to Fabiola, and making the royal family start paying taxes.
Fabiola married Baudouin in 1960, some nine years after he was crowned. Both were devout Roman Catholics and the king abdicated for a day in 1990 to avoid signing a bill to legalise abortion in Belgium.
The couple had no children and, when Baudouin died in 1993, he was succeeded by his younger brother Albert II. Fabiola later said that she had had five miscarriages.
Albert II abdicated in 2013 in favour of his son, Philippe.
After Baudouin's death, Fabiola made fewer public appearances, but remained involved in humanitarian causes, particularly children's issues and the rights of women in developing countries.