According to legend, the ancient founders of the city came from Palestine about 2500 years ago, a lost tribe fleeing a cataclysm.
This was a convenient belief in mediaeval times - it made the city older and more significant than Rome upon whom Henry VIII had viciously turned.
And it explains the meaning of the lines in William Blake's poem Milton:
"I will not cease from Mental Fight,Nor shall my Sword sleep in my hand:
Till we have built Jerusalem,
In Englands green & pleasant Land"
After the great fire in 1667, Christopher Wren with Nicholas Hawksmoor and James Gibb planned to rebuild the city actually as the New Jerusalem with St Pauls at the cosmic centre. They didn't manage to realise their dreams - their cosmically inspired geometric plan got lost in the labyrinthine archaic alleys and twisting patchwork of ancient ownership but they did manage to embed some of their occult ideas in the city fabric and, in Hawksmoor's case, in the buildings themselves. Hawksmoor was a freemason, a sinister, secretive and strange man. His churches are my favourites in the city. Some, like St Mary Woolnoth, are deeply weird and Iain Sinclair believes Christchurch in Spitalfields actually exerts a malevolent force on the neighbourhood.
But, when it comes to imaginary versions of the city, my favourite of course is the one depicted in Mary Poppins. Walking up Ludgate Hill, I am always half expecting to see her bustling along with her umberella.
If you are a fan of St Pauls by the way, you may be delighted to know that there is a tiny version of it held in the hand of one of the strange statues on Vauxhall bridge.
It is pretty difficult to see without falling into the river so mind how you go.