Goa, everyone agreed, was spoilt. Not what it was 20 years ago. Some people were snooty, as if I were going on a package holiday to Benidorm. Others were simply despairing, sighing that it had lost its magic, that it had sold its soul to charter flights and overdevelopment.

There were times when I wondered if I’d got the wrong Goa. I wandered south to Palolem, winding through the coconut groves, and found Goa so peaceful in the depths of a somnolent afternoon that I felt I could hear the dogs panting on the verandas of the old Portuguese houses.

At Cabo da Rama I stood on the ruined ramparts of the old fort, watching the swallows dive in the trade winds that bore the Portuguese caravels here 500 years ago. For as far as I could see, the coast looked as pristine as it would have done to those early sailors. A line of surf curled beneath gangly palms, where weathered fishing boats were drawn up on the white sands. Could this be the same place?

I realise now that the people who warned me off had been to Calangute, and were suffering from Blackpool syndrome. I once met an Algerian in Blackpool who expressed surprise that England consisted chiefly of carnival rides, ice-cream parlours and amusement arcades. I advised him to get out of Blackpool immediately. Once he got to the Lake District, he never looked back.

Calangute is indeed a messy confusion of concrete hotels, beach bars, souvenir shops, and sun loungers adorned with pink Europeans. I got out immediately. I wanted to find the parts of Goa that package tourism hadn’t reached, but I didn’t expect it to be so easy.

I rented a scooter and set off down the back roads. In 20 minutes I was in another world, on a rosewood love seat in a long gallery of Chinese vases and oyster-shell windows, having tea with Mrs Perreira Braganza. The house contained all the finery of a vanished imperial age — glass paintings from China, furniture from Macao, silver from England, marble from Italy.

Mrs Perreira Braganza ushered me through the ballroom, beneath the Belgian chandeliers, to the family chapel.

“We have an important relic,” she whispered. “The fingernail of St Francis Xavier.”

It’s true: the fingernail of St Francis can tell you much about Goa. A Portuguese colony marooned in British India, this has always been a place apart. Goans still speak a trifle disparagingly about India, as if it were a separate country; while Indians speak as though Goans are another race. In town squares where one might expect chai (tea) stalls, there are small bars and fish stalls. In the palm groves where one might expect temples and adobe villages, there are whitewashed churches and old villas with genteel balconies and shuttered windows.

Goa is South Asia’s Latin Quarter: indulgent, tolerant, capricious, steeped in a tropical lassitude and wedded to the sea. To explain themselves, Goans speak of susegad, a term whose translation depends upon whom you ask. It comes from the Portuguese word socegado, meaning quiet, which doesn’t really do it justice.

For Goans, susegad identifies a laid-back attitude to life. When I asked Mrs Perreira Braganza about it, she sniffed, “It’s nothing more than indolence.” When I asked her niece, she grinned and said, “Relax, take your time, enjoy life, be happy. That’s susegad.”

Susegad must have appealed to the Portuguese, a people inclined to take their time. Within 100 years of their arrival here, they had created one of the richest cities in Asia. It was also one of the most decadent. The sea breezes, the tropical languor, that old susegad, had conspired to make Goa an oriental fleshpot.

Which is where St Francis Xavier came in. Dispatched by the Portuguese king to reverse Goa’s moral decline, Francis spent 10 years in the east, before dying of a fever while trying to sneak into China. When the body was returned to Goa, its state of perfect preservation was greeted as a miracle.

Times recommends

• Oasis of the Seas: the Times review
• The 20 best new year party places to stay
• Green Spaces 2009: are you the winning writer?