London, UK - You might know him as Yahweh, Allah or God. But on this fact, Jews, Muslims and Christians, the people of the great Abrahamic religions, are agreed: there is only one of Him. He is a solitary figure, a single, universal creator, not one God among many.
Or so we like to believe. After years of research specialising in the history and religion of Israel, however, I have come to a colourful and what could seem - to some - uncomfortable conclusion: that God had a wife.
Archaeological evidence including inscriptions, figurines and ancient texts as well as details in the Bible, indicate not just that he was one of several worshipped in ancient Israel, but that he was also coupled with a goddess. She was worshipped alongside him in his temple in Jerusalem.
My interest in the Bible sprang from my fascination with my Greek heritage. Even though I was brought up in a secular household in London, religion was everywhere at home: storybooks retelling myths about the gods and goddesses of Mount Olympus sat alongside Greek Orthodox icons of the Virgin Mary.
I pursued it at Oxford, where I spent several years specialising in the cultural and social contexts of the Bible. I discovered that Yahweh, the God we have come to know, had to see off a number of competitors to achieve his position as the one and only god of the ancient Israelites.
The biblical texts name many of them: El, Baal, Molek, Asherah. Despite Yahweh's assertion in the Ten Commandments that 'You shall have no other gods before me', it appears these gods were worshipped alongside Him, and the Bible acknowledges this.
Far more significant is the Bible's admission that the goddess Asherah was worshipped in Yahweh's temple in Jerusalem. In the Book Of Kings, we're told that a statue of Asherah was housed in the temple and that female temple personnel wove ritual textiles for her.
In fact, although the Bible condemns all of these practices, the biblical texts suggest that goddess worship was a thriving feature of high-status religion in Jerusalem. What, then, was her relationship to Yahweh?
I attempted to track down this divine couple in my new BBC2 documentary series, Bible's Buried Secrets. Until the discovery in the early 20th Century of an ancient Canaanite coastal city called Ugarit in what is now modern-day Syria, very little was known about the goddess Asherah.
But ancient texts, amulets and figurines unearthed here reveal that she was a powerful fertility goddess.
But perhaps most significant of all, Asherah was also the wife of El, the high god at Ugarit - a god who shares much in common with Yahweh. Given the evidence within the Bible that she was worshipped in the temple in Jerusalem, might she have played the role of a divine wife in ancient Israel too?
Strikingly, Yahweh is often called 'El' in the Bible and he performs many of the same roles.
Despite numerous references to Asherah worship in the Bible, there wasn't enough evidence to link her explicitly with the high god of ancient Israel, Yahweh. Until, that is, the discovery of a remarkable ceramic inscription in the Sinai desert.
The inscription was photographed and recorded by archaeologists and scholars of ancient Israelite religion, so we know what it looked like - and importantly - what it said.
Dating to about the 8th Century BC, it was found at a remote site called Kuntillet 'Ajrud, and was written on a large piece of a broken pottery.
Its writer was probably a traveller or a merchant, moving between the towns of ancient Israel. For any traveller, a journey was dangerous, so divine protection was important.
The inscription is a petition for a blessing. Crucially, the inscription asks for a blessing from 'Yahweh and his Asherah'. Here was evidence that presented Yahweh and Asherah as a divine pair. And now a handful of similar inscriptions have since been found, all of which help to strengthen the case that the God of the Bible once had a wife.
Finding the original inscription, however, has proved impossible. Discovered in the Sinai in the Seventies, the real thing has since been mysteriously 'lost'. Neither the BBC team of researchers nor my academic colleagues and contacts could locate it.
The antiquities authorities of Israel and Egypt claim to have no knowledge of its whereabouts. Was the inscription simply a casualty of the bureaucratic confusion arising from the aftermath of the Six-Day War in 1967?
Or did someone take the decision that such a potentially unsettling piece of evidence about the Jewish and Christian God was better hidden?
God's relationship with Asherah was brought to an end with the rise of monotheism just a few centuries after our traveller inscribed his request for a blessing on an old piece of pottery.
Just as other deities worshipped in ancient Israel were relegated to become angels, or rejected as 'abhorrent', so too Asherah was done away with.
Consequently, two of the world's biggest monotheistic religions, Judaism and Christianity, now have at their heart a solitary male deity.
I can't help but wonder what the world would be like had the goddess remained.