By John Wilson
Presenter, Front Row
Shah Abbas was one of the formative figures in the creation of modern Iran
Across a conference table in an Iranian vice president's office, tea and sweet pastries are offered before cultural diplomacy.
An ancient clay cylinder, regarded by scholars as the world's first declaration of human rights, helps to seal a deal that could open a new diplomatic channel between Britain and Iran.
On the table is a symbol rarely seen in Tehran, unless it's being burned by protesters outside the British embassy. A mini Union Jack stands alongside an Iranian flag.
I'd been warned that, as a BBC journalist, I might not be welcomed into this Iranian government building in traffic-jammed downtown Tehran.
The launch of the BBC's Persia TV service has prompted a furious denouncement of British 'spies' in the country.
But as I've arrived in esteemed company, I'm waved through and - most surprisingly - offered a seat at the conference table.
On the table is a symbol rarely seen in Tehran, unless it's being burned by protesters outside the British embassy
To my left Neil MacGregor, director of the British Museum, whispers: "Well, that's a result."
Facing us on the Iranian side is a team led by a deputy vice-president.
Mr MacGregor's primary role is to secure the loan of artefacts, ornaments and Persian silk carpets for the British Museum's forthcoming exhibition Shah Abbas: The Remaking of Iran.
The third in a quartet of planned shows about great emperors, the exhibition will reveal how the roots of modern Iran can be traced back more than 400 years, to the reign of the greatest leader of the Safavid dynasty.
Jet set curator
Neil MacGregor has forged a role as Britain's cultural ambassador to the world.
He travelled to Beijing in 2005 with Tony Blair to sweet talk the Chinese into agreeing to the biggest ever overseas loan of Terracotta Warriors and other treasures from the court of Qin Shihuandi, the First Emperor.
When he returned to Beijing to sign the contract he arrived with a bottle of single malt Scotch and a DVD of Braveheart, having heard the Chinese culture minister was partial to a wee dram whilst watching Mel Gibson in a kilt.
The sweetener went down a treat.
Neil MacGregor's is a man of formidable energy and enthusiasm, power-napping his way around the world.
The Cyrus Cylinder, the world's first declaration of human rights
We had arrived in Tehran via a whistle-stop tour of Isfahan, a beautiful city whose bridges, palaces and mosques were thrown up in a celebratory flurry by Shah Abbas.
We'd flown in from London overnight, arriving at 5am before hitting the desert road for a five hour drive to Isfahan. Cramped and awestruck by the sunrise over an Iranian wilderness, I didn't sleep a wink.
As I stumbled off the bus, Mr MacGregor bounded into Naghsh-e Jahan Square with boyish excitement, leading the way through the bazaar to the best coffee shop and hubble-bubble hangout in town.
He has an encyclopaedic knowledge of the cultural history of the globe, casually peppering conversation with ancient dates and names and, by way of illustration, describing in loving detail artefacts from the British Museum collection.
One such object whose political and cultural significance resonates through history is the Cyrus Cylinder.
Created on the orders of Cyrus the Great, the Persian king who invaded Babylon and freed the people from slavery and tyranny, the clay object is a sort of 2,500-year-old Middle East roadmap.
The tiny cuneiform lettering records, in Babylonian, how every man, woman and child would now be free to practice their culture and religion.
The declaration, made in 539 BC, allowed the Jews, who'd been enslaved by Nebuchadnezzar after the destruction of Jerusalem, to return home.
The war question
The Iranian deputy vice president, sensing goodwill in the room, suggests a quid pro quo. He asks for the Cyrus Cylinder to be loaned to the National Museum in Tehran, a request quickly agreed by Neil MacGregor.
Then he says, through a translator, "there's the question of war".
He calls on Mr MacGregor to join with his counterpart at the Tehran museum in investigating the damage to cultural and archaeological sites in Gaza. Again, the British Museum man says yes, he'll raise the issue with Unesco.
Smiles are exchanged, tea sipped, and the contracts are signed to allow the Shah Abbass story to be told in London.
It's a good story. The Shah is credited with unifying a culturally and politically splintered country by creating a new sense of nationhood.
He decreed that the Twelver denomination of Shia Islam - which reveres the twelve imams who succeeded the Prophet Muhammad - would be the state faith.
Strict adherence to the theology was revived 30 years ago by Ayatollah Khomeini after the Revolution.
Shah Abbas was not simply a successful theocrat. In establishing his capital in the centre of Iran, he set about claiming Isfahan as the crossroads of the world by inviting trade from the Far East and the distant west.
Silks, spices and porcelain arrived at the Isfhan bazaar from China and India; from England and Holland, businessmen poured in laden with gold and silver.
The Shah struck deals with the East India Company in the early 17th Century and appointed an Englishman - Robert Sherley - as a sort of foreign secretary.
By the late 16th Century, even William Shakespeare was name-dropping his knowledge of the Shah with a line in the Comedy of Errors.
A merchant says: "I am bound to Persia and want guilders for my voyage." He is heading for the bazaar.
You can hear John Wilson's report on Front Row, BBC Radio 4 , Monday 19 January at 1915 GMT