YOU can't really get to grips with the numbers – the 18,500 children who were raised in Muller orphanages here in Bristol – until the charity's chief executive, Keith Hagon, opens the enormous wall-to-ceiling cabinets in his office.

There, neatly stacked in countless rows of immaculately labelled little cardboard boxes, are the records for all those individuals who found themselves in a Muller orphanage – stretching from the organisation's early days in the 1830s, right through to the final Muller orphans, who came through the doors in the 1980s.

"Right from the very early days, we always kept complex records," Keith says. "When a new child came in, every possible detail about his background was recorded – down to his parents' known medical backgrounds and the name of the individual who brought the child in.

"It was all valuable information for the Muller staff who raised the children, but today, it proves just as valuable for amateur genealogists who are researching their family tree.

"Sometimes when they reach the word orphan in their research, they expect the family tree to have reached a dead end. But not in the case of Muller orphans."

Among all these lists of individuals whose lives were shaped by the institution, one individual is alive and well at Muller House in Cotham more than any other.

There are photographs of George Muller everywhere you look – high collared, ramrod-backed and bristling with Victorian sideburns.

The museum room at the charity's headquarters also features a host of memorabilia from the founder's life – even his original desk.

After all these years, it somehow still feels like he is still in charge.

Muller was, by anyone's standards, a remarkable man. As a youngster growing up in his native Prussia, he had been a self-confessed thief, liar, gambler and drunkard. But in 1825 he underwent a dramatic religious conversion.

After training to become a preacher, he took on a position as pastor in Teignmouth in Devon.

But it was in 1830, when he moved to the cholera-stricken streets of Bristol, that Muller's mind first turned to the idea of establishing his own orphanage.

"At the time, there were fewer than a dozen orphanages in the whole country, and you needed wealthy backers to make it into any of them," explains Alan Jessopp, archivist and historian for the charity. "What George Muller did that was particularly radical for his time, was to set up an orphanage that would take any children free of charge.

"This was more than 30 years before Dr Barnardo arrived on the scene," he adds.

Muller had begun his time in Bristol by founding the Scriptural Knowledge Institution (SKI) in 1834 – an evangelical organisation, which still remains part of the George Muller Charitable Trust today.

But his place in the history books would be made with his passion for the orphanage he founded after witnessing the impact of the cholera epidemic on families in the city.

"He saw so many children living on the streets of Bristol, having lost both their parents to cholera, he felt he had to do something," Keith says.

"He was a strong believer in the power of prayer, and he is said to have prayed to God for help."

Soon after chatting with his "boss" on the matter, the pastor converted his own home in Wilson Street in St Paul's into an orphanage – with 30 youngsters being taken under his roof, to be cared for by Muller's ever-patient wife and friends.

As the decade progressed, so too did the number of orphans on Bristol's streets, and when three further houses became available in Wilson Street, Muller was able to raise the funds to buy them and convert them into children's homes.

But by 1845, with neighbourhood relations becoming a little fraught as the Muller orphans topped 130, the clergyman realised he needed bigger premises.

This time Muller managed to raise £10,000 in order to buy a rural site at Ashley Down, where the first purpose-built Muller orphanage was erected.

By the 1870s he had extended the organisations to cover five large properties at Ashley Down, housing more than 2,000 children at a time.

"He was extraordinarily disciplined – he had to be," Alan says. "Children wore uniforms, and lived a strict and well-ordered existence. But there was always plenty of love.

"One old boy told me the story he had heard from an earlier old boy at the home, who had been here in Muller's time. He was found by Muller, crying because nobody would play marbles with him. Despite being a very busy man, Muller found the time for the lad – he rolled his sleeves up and played the game with him there and then. That's the sort of man he was."

In his 70s, George Muller handed over the running of the homes to his son-in-law, not so he might enjoy a well-earned retirement, but rather so he could launch himself into an epic, 200,000-mile preaching tour, which would take him around the world and inspire numerous other Muller-style orphanages across the globe.

After Muller's death, at the age of 92 in 1896, his executors discovered he had almost no personal wealth – he had anonymously ploughed any income he received back into the charity throughout his life.

His funeral procession brought Bristol to a standstill as he was taken to his final resting place at Arnos Vale.

Following his passing, the organisation continued to evolve.

"The social care landscape changed over the years," Alan says. "Health care slowly improved and the numbers of orphans decreased. Also the government brought in pensions for the widows of servicemen killed in World War I, and as a result, fewer and fewer part-orphans needed to be given up to orphanages.

"By the 1950s the organisation had shifted to running a number of smaller homes, scattered around the city, and in 1986 we closed our last children's home."

But the organisation continued to help people in and around Bristol.

"We realised there was a growing need for elderly care for some of those who had started their lives in Muller orphanages," explains Keith.

"So for a number of years we ran a dedicated residential home for elderly Muller orphans at Weston-super-Mare.

"But gradually the need diminished as the orphans passed away, and we had to start taking in more members of the general public. This wasn't our specialism, so we sold the home a few years ago.

"Now we work on tailored projects aimed at helping young people in communities across the South West, through a network of more than 50 church groups which have Muller workers linked to them.

"It is a way for us to continue to keep the spirit alive of the organisation George Muller founded all those years ago."

For more information about the organisation, visit the website at www.mullers.org.