The next day we returned to Delhi to find that the storm had broken. The clouds were scudding low over the rooftops; it was pouring with rain and the streets were flooded. In the Old City, Muslim women were dragging their chadors like wet black crows. Gusts of rain lashed down the narrow alleys; rickshaws sluiced through the water, more like boats than bicycles. It was no day to be out, but I had an appointment to keep.

I had arranged to see Dr Yunus Jaffery, a historian and an archetypal Old Delhi-wallah. His ancestors had been Persian tutors at the Red Fort; today, Dr Jaffery pursued exactly the same career in Zakir Hussain College on the margins of Old Delhi. His rooms were in the original college, the Ghazi-ud-Din Medresse, a seventeenth-century Mughal building just outside the Ajmeri Gate.

Balvinder Singh dropped me outside during a brief pause in the rain. A low Mughal gateway led on into a wet and glistening flagstone courtyard; it was deserted but for a solitary pupil running late towards his class. The flagstones were slippery and so hollowed-out by three centuries of passing feet that along some of the walkways the puddles had coalesced into shallow canals.

The courtyard was bounded by a range of cloisters two storeys high. Classrooms filled the ground-floor rooms. On the first floor, leading off a covered balcony, were the chambers of the fellows and scholars. The arcades were broken on three sides by vaulted gateways, and on the fourth, the principal axis, by a red sandstone mosque. Before the mosque, filling both sides of the cloister garth, was a garden of healing herbs and shrubs.

I climbed a narrow staircase leading to the first floor balcony. Outside the scholars' rooms sat a line of bearded old men busily correcting specimens of Arabic calligraphy. Dr Jaffery’s room was the last on the corridor.

The door opened to reveal a gaunt, clean-shaven man. He wore white Mughal pyjamas whose trouser-bottoms, wide and slightly flared, were cut in the style once favoured by eighteenth-century Delhi gallants. On his head he sported a thin white mosque-cap. Heavy black glasses perched on the bridge of his nose, but the effect was not severe. Something in Dr Jaffery’s big bare feet and the awkward way he held himself gave the impression of a slightly shambolic, absent-minded individual: “Asalam alekum,” he said. “Welcome.” Then, looking behind me, he added: “Ah! The rains…Spring has arrived.”

Dr Jaffery’s domed room was small and square and dark. Lightning from the storm had cut off the electricity and the cell was illuminated by a bronze dish filled with flickering candles. The shadows from the candlelight darted back and forth across the shallow whitewashed dome. Persian books were stacked in disordered piles; in the corner glistened a big brass samovar incised with Islamic decoration. The scene of the Sufi scholar in his room was straight out of a detail from the Anvar-i Suhayli – or indeed any of the illuminated Mughal manuscript books – and I said this to Dr Jaffery.

“My nieces also tell me I live in the Mughal age,” he replied. “But they – I think – mean it as a criticism. You would like tea?”

Dr Jaffery blew on the coals at the bottom of his samovar, then placed two cupfuls of buffalo milk in the top of the urn. Soon the milk was bubbling above the flame. While he fiddled with his samovar, Dr Jaffery told me about his work.

For the previous three years he had been busy transcribing the forgotten and unpublished portions of the Shah Jehan Nama, the court chronicle of Shah Jehan. He had converted the often illegible manuscript into clear Persian typescript; this had then been translated into English by a team of Persian scholars in America. The manuscript, originally compiled by Shah Jehan’s fawning court historian Inayat Khan, told the story of the apex of Mughal power, the golden age when most of India, all of Pakistan and great chunks of Afghanistan were ruled from the Red Fort in Delhi.

It was an age of unparalleled prosperity: the empire was at peace and trade was flourishing. The reconquest of the Mughals” original homeland – TransOxianan Central Asia – seemed imminent. In the ateliers of the palace the artists Govardhan, Bichitr and Abul Hasan were illuminating the finest of the great Mughal manuscript books; in Agra, the gleaming white dome of the Taj Mahal was being raised on its plinth above the River Jumna.

The book which contained the fruits of Dr Jaffery’s labours was about to be published. Now Dr Jaffery was beginning to transcribe a forgotten text about Shah Jehan’s childhood. The manuscript had just been discovered in the uncatalogued recesses of the British Museum; it was exciting work, said the doctor, but difficult: the manuscript was badly damaged and as he had not the money to go to London he was having to work from a smudged xerox copy. The new transcription absorbed his waking hours; but, despite the difficulties, he said he was making slow progress.

“As the great Sa’di once put it: ‘The Arab horse speeds fast, but although the camel plods slowly, it goes both by day and night.’”

As we chatted about Shah Jehan, Dr Jaffery brought out a plate of rich Iranian sweets from an arched recess; he handed them to me and asked: “Would you not like to learn classical Persian?”

“I would love to,” I answered. “But at the moment I’m having enough difficulty trying to master Hindustani.”

“You are sure?” asked Dr Jaffery, breaking one of the sweets in two. “Learning Persian would give you access to some great treasures. I would not charge you for lessons. I am half a dervish: money means nothing to me. All I ask is that you work hard.”

Dr Jaffery said that very few people in Delhi now wanted to study classical Persian, the language which, like French in Imperial Russia, had for centuries been the first tongue of every educated Delhi-wallah. “No one has any interest in the classics today,” he said. “If they read at all, they read trash from America. They have no idea what they are missing. The jackal thinks he has feasted on the buffalo when in fact he has just eaten the eyes, entrails and testicles rejected by the lion.”

I said: “That must upset you.”

“It makes no difference,” replied Dr Jaffery. “This generation does not have the soul to appreciate the wisdom of Ferdowsi or Jalaludin Rumi. As Sa’di said: “If a diamond falls in the dirt it is still a diamond, yet even if dust ascends all the way to heaven it remains without value.””

I loved the way Dr Jaffery spoke in parables; for all his eccentricities, like some ancient sage his conversation was dotted with pearls of real wisdom. After the banalities of life with Balvinder Singh and Mrs Puri, Dr Jaffery’s words were profound and reassuring. As he told little aphorisms from Rumi or the anecdotes of Ferdowsi’s Shah Nama – the Mughal Emperors’ favourite storybook – his gentle voice soothed away the irritations of modern Delhi. But overlaying the gentle wisdom there always lay a thin patina of bitterness.

“Today Old Delhi is nothing but a dustbin,” he said, sipping at his tea. “Those who can, have houses outside the walled city. Only the poor man who has no shelter comes to live here. Today there are no longer any educated men in the old city. I am a stranger in my own home.” He shook his head. “All the learning, all the manners have gone. Everything is so crude now. I have told you I am half a dervish. My own ways are not polished. But compared to most people in this city…”

“What do you mean?”

“Here everyone has forgotten the old courtesies. For example… in the old days a man of my standing would never have gone to the shops; everything would be sent to his house: grain, chillies, cotton, cloth. Once every six months the shopkeeper would come and pay his regards. He would not dare ask for money; instead it would be up to the gentleman to raise the matter and to give payment when he deemed suitable. If ever he did go to the bazaar he would expect the shopkeepers to stand up when he entered…

“All these things have gone now. People see the educated man living in poverty and realise that learning is useless; they decide it is better to remain ignorant. To the sick man sweet water tastes bitter in the mouth.”

“But don’t your pupils get good jobs? And doesn’t their success encourage others?”

“No. They are all Muslims. There is no future for them in modern India. Most become gundas or smugglers.”

“Is learning Persian a good training for smuggling?”

“No, although some of them become very successful at this business. One of my pupils was Nazir. Now he is a big gambler, the Chief of the Prostitutes. But before he was one of my best pupils…”

At that moment, the cry of the muezzin outside broke the evening calm. Dr Jaffery rustled around the room, picking up books and looking behind cushions for his mosque cap before remembering that he was already wearing it. Muttering apologies he slipped on his sandals and stumbled out. “Can you wait for five minutes?” he asked. “I must go and say my evening prayers.”

From the balcony I watched the stream of figures in white pyjamas rushing through the pelting rain to the shelter of the mosque. Through the cloudburst I could see the old men laying out their prayer carpets under the arches, then, on a signal from the mullah, a line of bottoms rose and fell in time to the distant cries of “Allah hu-Akbar!”

Five minutes later, when Dr Jaffery returned, he again put a cupful of milk on the samovar and we talked a little about his home life.

“The death of my eldest brother in 1978 was the most important event in my life,” he said. “From my boyhood, I always wanted to live in a secluded place, to live like a Sufi. But since my brother’s death it has been my duty to care for my two nieces. I cannot now become a full dervish; or at least not until my nieces are educated and married. Until then their well-being must be my first concern.”

“And after that?”

“Afterwards I want to go on hajj, to visit Mecca. Then I will retire to some ruined mosque, repair it, and busy myself with my studies.”

“But if you wish to retire can’t you find some other member of your family to look after your nieces for you?”

“My elder brothers were killed at Partition,” said Jaffery. “My elder sister is also a victim of those times. To this day she still hears the voices of guns. You may be sitting with her one evening, quite peacefully, when suddenly she will stand up and say: ‘Listen! Guns! They are coming from that side!’”

“In fact it was only by a miracle that my sister and I survived at all: we took shelter with our youngest brother in the Jama Masjid area. Had we been at the house of my parents we would have shared the fate of the rest of the family…” Dr Jaffery broke off.

“Go on,” I said.

“My parents lived in an area that had always been traditionally Hindu. During Partition they went into hiding, and for a fortnight their good Hindu friends brought them food and water. But one day they were betrayed; a mob came in the night and burned the house down. We learned later that the traitor was a neighbour of my father’s. My father had helped him financially. This was how the man repaid him…” Dr Jaffery shook his head. “In this city,” he said, “culture and civilization have always been very thin dresses. It does not take much for that dress to be torn off and for what lies beneath to be revealed.”

Excerpted with permission from The City of Djinns, William Dalrymple, Bloomsbury.