For years they could only perform in secret. Now that has changed. Back then, I did have an excuse for such spectacular ignorance. For much of the 20th century this brotherhood of mystic dancers had been driven more or less underground by the Turkish government, anxious to keep a lid on religious movements which might undermine the new republic.
The dervish headquarters was turned into a museum in 1927, and thereafter the dervishes became a historical curiosity. A handful of die-hards kept the flame burning by meeting and dancing in secret. Even in today's more liberal times, when troupes are allowed to stage public performances in Turkey and tour professionally, their beautiful, uplifting ceremony remains forbidden in the shrine where their founder is venerated.
The complex of 13th-century buildings where the dervish movement took root is in the city of Konya in Anatolia. Konya, 160km south of Ankara, is one of the oldest continuously inhabited places on earth, but in modern times has become a thriving regional capital of two million people, with skyscrapers and malls to go with its bazaar and medieval mosques. It feels half a world away from the Turkey that most western tourists would recognise. In the streets, a high proportion of the women – young as well as old – wear headscarves in a city that is proud of its conservative ways. It took some serious foot-slogging before I managed to track down a hotel that served alcohol, and when I succeeded the concierge immediately gave me a knowing look as if to say "You don't have to explain – I know why you're here, " before directing me to the roof terrace restaurant.
To Turkish muslims – and especially to followers of the Sufi faith – Konya is the second most important place of pilgrimage after Mecca. One singularly remarkable man is responsible for this: Muhammed Celaleddin-i-Rumi – shortened to Rumi for Europeans, and Mevlana for Muslim followers – who was born in Afghanistan on 30 September 1207. The 800th anniversary of his birth will be celebrated tomorrow at Konya's football stadium, with the largest demonstration of dervish whirling ever staged.
Rumi's biography is part-documented, part-legend. We know that at 24 he became a professor of religious sciences. At the time, the region was part of the Seljuk Empire, and the local Sultan invited him to settle in Konya, where his gifts could flourish. There Rumi met a Sufi mystic who inspired him to devote the rest of his life to God. He expressed his mystic philosophy by giving full rein to the normally non-religious arts of literature, music and dance. The stuff of legend is how the whirling dancing – the sema – came into being. The story goes that one day in the Konya bazaar, Rumi was watching a friend at work, hammering gold into shape to make an ornament. He began to move to the rhythmic tapping of the goldsmith, turning, turning and turning again until he whirled himself into a trance. When at last he stopped, the piece of gold broke into pieces.
"When I saw the ritual for the first time, I wanted to be a dervish with all my heart," says Mete Horzum, 30, one of 200 dancers in Konya who are permitted to give public performances. Mete's troupe has performed in the US and Germany, but he has never been able to perform the sema inside the shrine at Konya itself, where Rumi is buried. The shrine has been rebranded by the secular authorities as the "Mevlana Museum", where religious ceremonies are not allowed. .
Banned as a religious movement, the dervishes are now allowed to perform in public, because the sema has been officially sanctioned as a "cultural" attraction. Private groups perform in small venues, and on the outskirts of town the Ministry of Culture has built a new performance centre that stages ceremonies in summer, one of which I witnessed in August.
The lights go down as 13 dancers and nine musicians wearing cone-shaped red hats solemnly take up their positions and remove their black cloaks to reveal their distinctive white "skirts". For the next hour, through seven ritualised stages of music, incantation and dance, they act out the mystical ascent of an individual towards union with the divine.
Every element of the performance is drenched in symbolism – the skirts represent the ego's shroud; the wailing, flute-like ney music is the breath of God. The dancers rotate on their left feet in short twists, using their right leg to drive their bodies around. The outfits billow and spin as the dancers whirl in harmony with the rhythms, slowly picking up speed.
"Performing the ritual is like a meeting with God," Mete had told me. "There are some very special moments when I'm transported from the world around me. When I don't feel good, it's like a medicine. Dancing clears the mind."
And then the dervishes' journey is over. The music stops, they put their cloaks back on and leave the circular stage as slowly and silently as they arrived. There's no applause: the audience appreciates that this is serious stuff, nearer religion than entertainment. They file away silently, visibly relaxing as they hear music and cheering from a very different event at the adjoining outdoor arena. Another crowd is letting its hair down to enjoy a colourful and, by local standards, risque performance from a visiting group of female folk dancers from Bosnia. The dervish-watchers eagerly join the throng, like sombre church-goers at the end of Sunday service, discovering an ice cream van parked a little way down the road.
The writer travelled with Anatolian Sky Holidays (0800 247 1011; www.anatolian-sky.co.uk), which organises tailor-made packages to coincide with whirling dervish performances. A four-day trip to Konya from Heathrow (via Istanbul), including scheduled flights with Turkish Airlines, transfers and B&B at a three-star hotel in Konya costs £499 per person. A 10-day "three centre" itinerary, including transfers to Cappadocia and Istanbul, costs £999 per person. Guides are available on request.
Konya is served only by Turkish Airlines (020-7766 9333; www.thy.com ), which flies daily from Heathrow via Istanbul. By road, the city is three-four hours from the capital, Ankara.
Directorate of Culture and Tourism, Konya (00 90 332 353 4021; e-mail: kultur@ konya.gov.tr)
Turkish Culture and Tourism Office, 29-30 St James's St, London SW1 (020-7839 7778; www.gototurkey.co.uk )
For more on the 800th anniversary celebrations, the dervishes' official website is www.rumi2007.net