The spirit of a pure Christianity: Exploring Ethiopia's stunning subterranean churches

I wake up and don't have a clue where I am. There is barely any light, hardly enough to pierce the curtains. But it's not the gloom or the early start that has left me confused. It's the ear-splitting chanting.

The noise is in no language I've ever heard. Yet the sound is familiar, even if the language is not. I have heard it in Istanbul, the Gulf, parts of Jerusalem. It sounds almost exactly like an imam calling the faithful to prayer.

Yet I am in Ethiopia, the cradle of an ancient form of Christianity, and the hotel at which I am staying is in Lalibela, one of the country's most Christian sites; there are no mosques nearby. So what is going on?

Stepping out on to my balcony, I see the hillside opposite covered with thousands of people dressed in white cotton robes. They are making their way up a series of dirt tracks, their feet throwing up a haze of red dust. The chanting seems to be coming from the hilltop. But there is no sign of a church or indeed any building up there. All that can be made out is the rough outline of part of a giant cross, seemingly carved into the ground.

My guide, Girtane, is waiting for me in the hotel lobby. Seeing my confusion, he breaks into a broad smile. "It's St George's Day," he says in explanation. St George, I learn, is the patron saint of Ethiopia. The damsel whom the knight saved from the dragon is, in local tradition, an Ethiopian princess called Beruktawit. And the chanting is not Arabic but Ge'ez , the holy language of the Ethiopian Orthodox Church.

Ge'ez has been spoken in Ethiopia since the time Rome was first founded. It has been the language of the Ethiopian Orthodox Church's religious texts since Christianity originally spread to the country in the early fourth century, brought to this land by a Syrian Greek shipwrecked on the Eritrean coast.

The reason it sounds so familiar is that its origin can be traced to the same linguistic roots which inform Arabic and Hebrew. Ge'ez, it seems, is just another of the many ways that Ethiopia, and its church, has long been entwined with Mediterranean and Middle Eastern – and not just African – tradition.

I had already been in the country long enough to appreciate its rich cultural heritage and how it is a very, very different place to its Live Aid-era image. The capital, Addis Ababa, is a hive of construction (much of it the result of the influx of vast sums of Chinese money). Great stretches of the countryside look lush and green. But, for me, the biggest revelation in my time there was about the Ethiopian Orthodox Church, and its relationship with the people it serves.

Ethiopia was cut off for centuries from the wider Christian world by the Islamic conquests to its north. During that time, its church flourished in isolation, untouched by and ignorant of the theological disputes dividing Europe. That means its traditions provide insight into an older, perhaps purer and certainly more mystical form of Christianity – one that dates back 1,600 years and therefore, in its unaltered forms, bears witness to a liturgy practised only a relatively brief period after the time of Jesus Christ.

To better understand this, I had come to Lalibela, Ethiopia's self-proclaimed "New Jerusalem". Here, I thought, I could engage with the religion and its beliefs. What I had not expected was that I would also get to see one of the world's most impressive – and most affecting – architectural marvels.

It was the fall of the Holy Land to Saladin 900 years ago that prompted these remarkable structures to be built. Ethiopia's new king, King Lalibela, determined that his subjects, as well as the small Christian states scattered along the Nile, should have their own "Jerusalem" at his capital, Roha, to visit in order to show their devotion.

King Lalibela is so surrounded by legend that it is almost impossible to separate the man from the myth. Even his name, meaning "the man bees obey", is part of that mystique. At his birth, a swarm of bees supposedly settled upon him, covering him but not stinging him. Later, when aged around seven, it is written that he was lifted towards heaven and spent three days receiving instruction on God's divine knowledge.

The stories may be fairy tales but the monument he created – and which now bears his name – leaves no doubt as to the power he wielded. Claiming the plan had come to him in a dream from an angel, Lalibela instructed that a series of churches be constructed from the rock itself. This meant they were not built up from the ground with stone or brick but actually chiselled out of the surrounding hillsides.

By the early 13th century, 11 churches had been built. The labour involved must have been immense, not least as many are dug out of red volcanic rock. Some of the churches are constructed across the sides of valleys. Others are built deep into ravines, the result cave-like. Many are linked by subterranean tunnels. A river was re-routed and re-named the Jordan. The largest hill overlooking the site became the site's own Mount Tabor.

No one is sure just how long the project took. Locals often say 23 years – but that is based on the legend that angels themselves came to help work on it, taking over at night as the human workers went home to rest. Without any records from that period, it is not even known how those humans who did toil on the site were housed or fed.

Nowhere in Lalibela is as impressive, however, as the building they finished last. That is the Bet Giyorgis, or the Church of St George, and it is there – it being St George's saint's day – that the crowds are gathered and from where the chanting comes. The surrounding roads heave with pilgrims, some beating skin- covered drums and others waving sticks covered in bells, as around them children dart, selling crucifixes fashioned from dried reeds.

The only way to properly appreciate the Bet Giyorgis is to look down upon it. Dug directly into the hilltop and standing 50ft tall, it is shaped like a giant Greek cross and is set tight within the walls of the surrounding pit. Once the ground was chiselled away by hand to create the monolith, the exterior carvings were completed and the interior hollowed out.

There are no souvenir stalls or safety rails here, health and safety concerns being notably absent. Rather, the pilgrims descend rough-hewn steps. Reaching the church's entrance, many kneel to kiss the ground. Outside is a small baptismal pool, overgrown with grasses used in Palm Sunday services; inside, the only light flows through narrow windows high up in the wall. On the day I visit, a priest stands in a corner holding burning candles that he waves in front of him. Another wafts a censer, the smoke billowing towards us, as other priests line the walls.

The faithful enter and prostrate themselves forward to pray. "They've come here for a blessing," it is explained to me. "We're taught that every believer must come at least once in their lives to Lalibela. Some will have brought family members who are sick or disabled, as it's believed the holy water has healing properties. Many will stay all day and all night."

A curtain separates the inner area reserved for the priests from the main room holding the faithful. A third section stands at the centre of the church. This is its most holy spot and none but the most senior clergy are allowed to enter. It is there – as in all Ethiopian churches – that a representation of the Ethiopian Orthodoxy's most revered object stands: the Ark of the Covenant.

The Ark, the Bible tells us, held the Ten Commandments given to Moses on Mount Sinai. For the rest of Christianity, it has been lost – most likely stolen or destroyed in the sixth century k by the Babylonians when they sacked Solomon's temple. Not, however, for the Ethiopians. They believe they know exactly where it is; indeed, that it has been in their homeland for thousands of years. Since the 1960s, in fact, it has been housed in a special chapel near an Ethiopian town called Aksum, where it is guarded by a succession of virgin monks who are never allowed to leave the chapel's grounds.

The Queen of Sheba is at the heart of the tale of how it supposedly got there. Travelling to Jerusalem, she is said to have met and fallen in love with King Solomon and, unknown to Solomon, had a child with him called Menelik.

This child would become the first emperor of Ethiopia and ultimately return to Jerusalem to reveal himself to his father. Legend has it that Solomon was delighted and bestowed upon his son all manner of gifts, including a retinue of nobles to protect him on his journey home.

What actually happened next is confused. According to some traditions, it was this noble retinue who stole the Ark without Menelik's knowledge; according to others, that he colluded with them; and in some accounts that the whole endeavour was set up and supported by the Archangel Gabriel. The result, however, is agreed upon: the Ark of the Covenant was taken to Ethiopia, where it has stayed ever since as a symbol of God's blessing.

I travel to Aksum, hoping to see the Ark for myself. I quickly discover that there is no chance of that. No one other than its elderly guardian is allowed to set eyes upon the relic – not the country's president nor even the Ethiopian Orthodox Church's patriarch. The chapel proves to be little more than a concrete box with no architectural interest or style. Standing behind spiky iron railings, it looks like nothing more than a suburban bungalow. To my surprise and disappointment, there is no sense of the sacred here.

The contrast with Lalibela could not be greater. There, you find pilgrims praying, kissing the walls or sitting cross-legged on the floor reading religious texts. Every morning a service is held in all the churches. Lalibela is a place where worshippers' faith brings life to ancient walls in the most profound manner.

As a Russian, I come from a country that is part of the Orthodox tradition. Culturally, the Russian Orthodox Church is my church – although little I have seen ever enamoured it to me. One only has to consider its hounding of punk-rock protesters Pussy Riot, or its cosy relationship with the state, or the sense of avarice that seems to emit from it, to realise why. In recent years, reports have emerged that a car repair and tyre service was being run underneath Christ the Saviour, Moscow's largest Orthodox cathedral, and that a brothel was being run on land rented by Sretensky Monastery. Archpriest Mikhail Grigoriev of Kazan was discovered to own a BMW jeep, a Mercedes jeep and a Mercedes saloon as well as three flats and a country house. He was secretly filmed boasting about his £12,000 mobile phone and love of Italian designer clothes. This year, there have been allegations of sexual assault by Russian Orthodox clergy, with students supposedly plied with alcohol before being abused.

The church's head, Patriarch Kirill, a man who regularly criticises Western commercialism and publicly called feminism "very dangerous", was even caught out by his own hypocrisy: two years ago, his press team issued a photograph of a meeting in Ukraine in which Kirill's $30,000 Swiss Breguet watch was airbrushed out. Unfortunately for them, they had overlooked its reflection on a polished table top.

Ethiopia's Orthodox Church appears very different. On the ground, the impression I get is overwhelmingly one of a clergy committed to personal humility. Again and again I meet priests living lives just as humble as their congregations. They are keeping true to the tenet of their faith that they must forgo almost all possessions and dedicate themselves totally to the spiritual life. This, I feel, gives them considerable moral authority.

After Lalibela, Tigray, to the north, is perhaps Ethiopia's most sacred spot. Amid its stark, lunar-like mountains, with their steep outcrops and columns rising hundreds of feet into the air, are built Tigray's own rock-hewn churches. Some of these predate Lalibela's by hundreds of years and, though less impressive architecturally, have their own power brought by the isolation and otherworldliness of the spot.

Access to many involves scaling a cliff. Again there is no health and safety procedure – or even ropes and carabinas – and I find myself clinging to a sheer rock face seeking out the next crevice as I inch myself towards the top to see one of the churches for myself. There I meet the local bishop, who invites me to his home in a nearby building. It is utterly spartan. A thin mattress on the floor, a beaten-up wooden chest and an old clock radio are seemingly his only possessions. I ask if he doesn't miss having a few luxuries. The answer is immediate: he does not, he insists. Despite his being a "simple life", for almost four decades he has got all he needed or wanted from life as he has been able to spend every day "praying".

As I leave, a group of pilgrims arrives to see him. Standing outside his church, he blesses them. Then he goes inside to get what food he has to share. Together they break bread.

Inside the church would have stood its replica of the Ark, the symbol of God's promise to his chosen people. Yet what I witness is a living, more immediate, covenant – one that across the country is renewed daily between a church and its believers. If there must be religion, I tell myself, then this is how it should be.

Evgeny Lebedev is the owner of the Independent titles and the London Evening Standard. Follow him on Twitter at @mrevgenylebedev