By Charles Haviland BBC correspondent in Hyderabad

The Sidi ancestors were guardsmen brought over by Muslim rulers

We talked while Mohammed's young grandson looked shyly on.

Mohammed, who is in his 70s, is one of Hyderabad's Sidis - a community of people of African descent.

While some of India's Sidis came as slaves, this southern city's community has its roots in a troop of guards recruited to serve the Nizams - the old Muslim dynasty of this one-time princely state.

The story goes that in the 19th century, the 6th Nizam got word of Africans serving in the court of another Indian nobleman.

Impressed by their qualities, he asked for a batch of Africans to be brought to Hyderabad. A group of around 300 soon followed.

Most accounts suggest they came from Africa voluntarily.

They included Mohammed's grandfather.

"My grandfather came from British Somaliland, from Hargeisa. My father was born here," he told me.

Nothing African is left - no music, no clothes; everything is Indian Mahmud bin Farzullah

Showing me some family photos, Mohammed pointed out his maternal grandfather and uncle, both of them in the Nizam's African Cavalry Guards or "AC Guards".

The military staff also included Arabs, but the Nizams had wanted Africans as bodyguards "because they are loyal, and physically good", he told me.

Also pictured are a number of Ethiopian Christians.

The part of Hyderabad where most Sidis live today is known simply as AC Guards.

It has a pronounced Muslim feel to it, centred as it is around an old mosque; Muslim businesses including beef butchers line the lanes.

But also in the neighbourhood is a large church - St Mary's.

In these streets, most people you see are not Sidis. But some of the local Sidis are highly venerated.

Vivid memories

Mahmud bin Farzullah believes he is at least 100 years old and has South African ancestry.

He was a guard for the seventh and last Nizam, who lost his powers in 1948 when India, with great violence, took over Hyderabad.

"I used to ride horses, do horse-jumping and the daily parade," he told me.

Hyderabad's AC Guards district still has a distinctly Muslim feel

"I was also part of the contingent that used to greet the Nizam on his birthday and present him with gifts."

The last Nizam was extremely eccentric, but for Mahmud, "he was a great person. He really loved his people."

The memories are equally vivid for a non-Sidi I met - Mir Moazam Hussein, now nearly 90.

As a member of Hyderabad's old nobility, he and his cousin, as young boys, used to sit under the Nizam's balcony on the royal birthday for a prime view of the AC Guards.

"They were the most brilliantly-attired, uniformed men; the men did justice to the uniform - they were great big dark-skinned men, you know. And so were their horses!" said Mir Moazam.

He has sweet memories of the AC Guards playing the military band, and of some of them coming to his boyhood palace selling duck and snipe which they had shot on Hyderabad's lakes.

The palace had a staff of hundreds, including Sidi women, the female relatives of the guards, who would check in visitors.

Only Urdu

The Hyderabad Sidis still excel in music.

One man I met, Abu Pahalwan, runs a band of drums which plays at weddings and sounds unmistakably African.

They have also scored outstanding feats in sport, especially hockey.

But I got the sense that this community had fallen on hard times.

"In the past, people used to respect us," Mahmud bin Farzullah says.

A Sidi music group performs at the recent Zanzibar film festival

"But now, when they realise we are Sidis, they move away from us. They don't want to talk to us. And this government gives jobs only to Indians."

Because men vastly outnumbered women in the African immigration to India, with each generation the African blood is diminished.

I was struck by how much the Sidis have lost touch with their African cultural roots, apart from perhaps in music.

Many do not even know what part of Africa they are descended from.

"The Ethiopians here speak only Urdu - me too," Mohammed bin Hassan told me.

But he has no regrets about having lost his Somali culture.

It is the same for Mahmud bin Farzullah.

"Nothing African is left - no music, no clothes; everything is Indian," he said.

But he does feel sad that more and more young people are marrying outside the Sidi culture.

The Nizam's Sidi guards were just one in a series of African immigrations to India over the centuries.

But it was never a mass phenomenon.