Nigel Nicolson says that some houses, like some people, are immediately likeable, while others take time to know. The mid-nineteenth-century summerhouse on the upper shores of the Bosphorus owned for three generations by the Ratip family – and now by the Mardin family – belongs firmly in the former category.

It stands on a sheltered curve of the channel between the villages of İstiniye and Yeniköy. Enclosed by high walls, hidden from passers-by, its charms are as fresh to those who have known it a lifetime as to those whose first visit was yesterday.

The wooden yalı was originally built as one of a pair. They were probably the first substantial constructions ever, or at least for many centuries, to have stood on the site, for this had once been monastery land. Sadly, its twin has gone, torn down in the 1930s to make way for a fashionable New Republic summerhouse in a style best described as Bosphorus Third Empire.

The deceptively simple exterior of the Ratip Efendi Yalı conceals a wonderful and richly decorated interior, set off by a breathtakingly elegant flight of stairs which winds up through the house. It is generally supposed that the twin houses were commissioned by some well-connected pasha as dowry pieces for his daughters, though no records survive of when, or how, they were built, or of any architect. They were almost certainly the creation of local master craftsmen, their prodigious talents passed down from generation to generation.

Viewed from the water, the yalı lies palely beautiful amid its own mature trees. Huge magnolias, a dozen palms, together with pines, cedars, Judas trees and overgrown laurels, run riot up the hill by which the yalı is cushioned; they do battle with armies of giant hydrangeas, rambling roses and cords of entwined wisteria. The perimeter walls and fine entrance gates enclose a full acre of ground, cut into terraces on three levels.

The hillside itself is dotted with springs. These waters have been channelled through finely decorated fountains to cascade into a series of oval fish ponds dug into the terraces. Close to the shore, between the boathouse and the yalı, a freshwater spring bubbles up through clear sand. As a shrine dedicated to St George, its walls are covered in frescoes of uncertain date. The therapeutic properties of these waters may well have been known from as early as the time Jason sailed by with his Argonauts, and villagers still come with their jugs when there is sickness in the home.

Rushing around as we do today, hostages to mobile phones and laptops, it is hard to conceive of those long, leisurely sojourns on the Bosphorus enjoyed by a throng of Turco-Egyptian textile magnates known as the Mısırlılar. Each summer from the 1850s to the 1960s, they migrated here from their palaces in Cairo and their hôtels particuliers in Europe. Reckless spenders, they came to enjoy the fruits of the nineteenth-century cotton boom. Following a vogue set by the Khedives themselves, who had built a series of summer palaces on both sides of the water, they arrived by car, by train or by boat as the wisteria came into bloom. Like homing pigeons returning to an old-fashioned loft, they settled, with their entourages of servants, into the yalıs they had bought or built beside the Bosphorus.

The Ratip fortune had been made in one generation by an exile of the Ottoman Empire who had fled to Mehmet Ali Pasha’s Egypt after his father had fallen foul of Sultan Mahmud II. It is thought that he acquired the yalı in Yeniköy – a property complete with a house ideal for generous entertainment and useful for accelerating acceptance in the capital – sometime during the l860s.

By the turn of the century, Ulfet Hanım, his half-Egyptian daughter, was spending her summers happily ensconced in the yalı, conducting her fashionable life in many tongues. She is remembered particularly for her love and knowledge of Turkish classical music and for the evening concerts she gave in the house. But it was to be during the lifetime of her son, Ebubakır Ratip, that the yalı took on its role as cultural crossroad between Europe and the Middle East for which it is most vividly remembered.

During the four-month, summer-long stay in the yalı, one day merged into another. It was open house. Swimming parties led to lunch; fishing, sailing and rowing parties led to five o’clock tea and idle gossip around a samovar in the shade of a spreading umbrella tree. Gone is the sight of “Papa and Mama Ratip” passing through the yalı’s handsome gates in their Rolls-Royce, their huge Egyptian chauffeur in full uniform and fez at the wheel. Ebubakır Bey was a rotundly handsome figure with monocle and moustache, Ceyda Hanım a beautiful woman in Paris’s latest New Look. Gone, too, are the Fifties sports Mercedes, the seven live-in servants – an international household led by Beshir, the striking Sudanese whose shiny black shoes, well-ironed trousers, white jacket and fez made him the mascot as well as the major-domo of the house.

Ebubakır Ratip died at the age of eighty-five, in 1977, his substantial inheritance all but eaten up. His wife outlived him by three years. They were the last truly colourful Mısırlı family to summer on the Bosphorus. They were both bound, either by friendship or by blood, not only to almost every member of the international café society who took their motorboats and water skis to the French Riviera, but to nearly every member of the then ruling families of the Middle East.

It is difficult, half a century later, to unravel the complex relationships between members of the Ratip circle. Ebubakır Bey’s connections were mainly Turco-Egyptian ­– he was related to the Khedive – but a Ratip nephew was married to Fevziye, the former Empress of Iran. His wife, Ceyda, provided further cosmopolitan links. She was the eldest of the newspaper proprietor Ahmet Cevdet İkdam’s three daughters. Her half-Russian mother, a concert pianist, was the daughter of a St Petersburg court jeweller. Her first husband, killed in a car crash in the South of France, had been Prince André Obolensky. As a young widow, staying in Cairo with her middle sister, Reya, in the early 1920s, Ceyda met, and later married, Ebubakır. Reya’s husband was the Turkish diplomat Şemsettin Arif Mardin, son of the last governor of Syria and the Lebanon, and the legendary Leyla Hanım Efendi, daughter of an Egyptian diplomat, who had been brought up in the embassies of Paris, Vienna and St Petersburg, watching her father’s paintings by Corot, Courbet, Boucher and Ingres being added to the walls. It was in her Cairo palace that the introduction was made.

During the summer of 1957 the Ratip summerhouse on the Bosphorus contributed a bright thread to the tapestry of history. The crowd of friends who that year came daily to swim from the terrace included foreign diplomats down from Ankara (the French, Italian, Swedish and Greek ambassadors), neighbours dropping in from up or down stream, the Princesses Neslişah and Hanzade, grandchildren of the last sultan, still unable to own property on Turkish soil, with their own children, and the young King Faisal II of Iraq.

The King arrived every day at nine in the morning and left at three the following morning, for he was courting Princess Fazileh, the beautiful daughter of Hanzade Sultan, to whom he became engaged in the coolness of the yalı. When she received his emerald ring, she could not have imagined that a year later her short, plain but charming fiancé would be murdered, following the Baghdad Revolution of July 1958, or that later, married to Hayri Ürgüplü, she would sell the ring to pay for her own yalı.

That summer, the young king’s suave, good-looking, pro-English uncle Abdülilah, then acting as regent of Iraq, came regularly to tea carrying a grey cat on his shoulder, which he stroked constantly. He, too, was foully murdered following the July Revolution.

Less regularly, the diminutive but handsome young King Hussein of Jordan arrived, not with his Hashemite cousin Faisal, but with the Egyptian Prince Mehmet Ali, Hanzade Sultan’s wealthy husband, who moored his yacht on the yalı’s quay.

A year before King Faisal’s engagement, on July 14, 1956, the roads were closed along the European shore to allow a cavalcade of cars to flow in the direction of Yeniköy for the biggest wedding in Istanbul since the war.

The marriage of Reya Mardin’s son Şerif was being celebrated in the yalı. His bride was Suna Aksoy, the beautiful daughter of the successful bureaucrat and honorary consul in Monte Carlo and his İzmirli wife, whose family had owned cotton fields in the Menderes delta for generations.

Those who glimpsed the bride and the throng of wedding guests passing on their way could not be blamed for imagining that the disruption was in honour of Turkey’s beauty queen: if they failed to recognise the crownless King Umberto of Italy with his sister, the ex-Queen of Roumania, certainly the young Bülent Ecevit, later a regular guest, will have passed unnoticed by the watching crowds.

The fifty-year marriage of Ebubakır and Ceyda Ratip was childless. When she died in 1980, the yalı was passed to Osman, the son of Şerif and Suna Mardin, grandson of Reya, Ceyda Hanım’s younger sister, and so Ebubakır Ratip’s great-nephew by marriage.

The Mardin Yalı, as it should now be called, has recently been lovingly and impeccably restored and is in hands as safe and as sensitive to its history as any yalı on the Bosphorus could hope to be.