She affected musical history not only in Portugal but in Europe has a whole - not so much through whom she knew, but because of whom she helped, from Poulenc to Rubinstein, from Stravinsky to Daniel Barenboim. Vladimir Ashkenazy, who took refuge with his wife at the Marquesa's house after their precipitate flight from Soviet Russia, paid tribute to her as their "mother hen".
Olga Nicolis de Robilant, descended on one side from Catherine the Great and on the other from a long line of Venetian doges, was born in Turin in 1900. She grew up in a cultivated home where the casual guests included Verdi, d'Annunzio, Diaghilev and Nijinsky. One of her childhood friends, with whom she remained close until his death, grew up to become Pope Pius XII. Cole Porter serenaded her at a bar on the Venice Lido; Chaliapin sang for her; Ravel, with whom she later kept up a long correspondence, wrote music for her. Another childhood friend was the stepdaughter of Puccini, who taught both girls to dance. "We loved his music," she recalled, "but with us he was very modest. He used to say, `All my music is good for is making housemaids cry.' "
At 14, shocked by the realities of war, she joined the Red Cross as a volunteer. Her first foray into musical patronage came when, as a student of 20, she persuaded Rubinstein to give his services free for the inaugural concert of the Amici della Musica in Florence. One of her most exhilarating memories was of Rubinstein, Ravel, and Stravinsky all staying together at her house.
Her friendship with Stravinsky had a macabre ending. "When he was terminally ill," she told me, "he sent a message that he loved my house so much that he wanted to die there. But I thought, I can't have this. If he dies in my bed, what do I do? Do I burn it? I certainly couldn't sleep in it afterwards. And I don't want the widow and his friend Robert Craft hanging about grieving afterwards. So I said, `I'm sorry, I don't want him to die here. Tell him I hope he gets better.' " He died elsewhere, and - to her relief - before her message of rejection reached him.
She had acquired her house in Sintra through marrying Antonio Alvares Pereira de Melo, the exiled Marquis de Cadaval. It had been a ruin, so she rebuilt it and laid out the gardens. Prematurely widowed at 38, she decided to turn it into a musical Mecca.
When Francis Poulenc organised a performance there of his opera Les Dialogues des Carmelites, it was as a thank- offering for her prayers during the Second World War, when he had been convinced - as she had been - that he would be killed. She had buoyed him up with parcels of cheese and coffee, to which he responded with parcels of sheet music. Her patronage was eminently practical.
As time went by, a constant stream of young musicians passed through her doors, each given a room and carte blanche to spend their days as they chose. "One day," she recalled, "an impresario told me that he was going to make me a present in return for the wonderful times he had had at my house. He said, `I'm going to send you an unknown artist, who I think you will like. Her name is Jacqueline du Pre.' "
The Marquesa did not know her, but sent a telegram inviting her to stay. "The house was full of musicians, but she immediately became the centre of things, playing day and night, and getting cross because when she got up and was ready to play, everyone else was still asleep. A few months later she rang and said she had met someone with whom she was madly in love, and could they honeymoon in my house?" So that was where she and Daniel Barenboim spent their first married weeks.
Musical life in Portugal had been a stunted affair until the Marquesa - abetted by the Gulbenkian Foundation - erupted on to the scene. She steered a masterly course through the political rapids before, during, and after the "Carnation" revolution. For her concerts she persuaded Salazar - a man who abominated Jews and Communists - to let her import both, and in large quantities. "I simply told him, if you want the best, you must let me have my Russians." His condition, which she happily met, was that she should lodge them in her house, and take full responsibility for their behaviour.
The revolution, she admitted to me, was a shock. "I admired Salazar very much, and am still dedicated to his memory. But - things finish!" Whereupon she shrugged, smiled, and walked off into her rose garden.
She was a woman of easy grace, completely devoid of pretension; she enjoyed good health - fortified by wine from her own vineyard - almost until the end. She died peacefully, buoyed up by her religion, with her family and friends around her.
Olga Nicolis de Robilant, festival organiser: born Turin 17 January 1900; married 1926 Antonio Alvares Pereira, Marquis de Cadaval (died 1938; one daughter, and one daughter deceased); died Lisbon 21 December 1996.