Almost 600 years ago, Henry V created the world's first passports. They were designed to help prove who you were if you travelled to a foreign land.
Within weeks, people who have come from abroad will be the first people in modern Britain to be given ID cards.
From late November the UK Border Agency will roll out the first part of the controversial identity card scheme which, Parliament permitting, will register everyone living in the UK.
At present, a legally-resident foreign national has a sticker or stamp in their passport. If they go for a job, a scrupulous employer can make checks to ensure they are not about to employ an illegal immigrant.
That's all changing.
The new cards, complete with fingerprints encoded on a chip, replace the passport stickers.
They will initially only apply to people who live in Britain as a student or through a marriage visa - a small proportion of the overall number of migrants.
But eventually, any foreign national from outside the European Union over the age of six will be called to an immigration agency office and asked to put their hands on a scanner.
The card, rather than the passport, will become proof of a holder's right to stay, work or study in the country. It will be a recognisable form of identification for opening a bank account or applying for benefits.
But are the cards really needed?
The UK's immigration system is halfway through its own cultural revolution with ministers trying to win back public trust.
Government needs to convince people times have changed - and biometric, secure identity cards are part of that story.
Supporters of cards predict they will help to combat illegal working and enable public bodies, employers, colleges to work out precisely who they are dealing with.
But according to critics, the second reason for the cards is more political.
Officially, the cards are not part of a National Identity Register - the grand machinery which underpins the whole idea of a universal card.
They are in fact a residence permit similar to other EU schemes.
Home Office opponents accuse it of playing a very clever game with foreign national identity.
The people selected for the first wave of cards will have no choice - it will be part of the process of a legal right to stay.
The next group to receive ID cards will be anyone (including Britons) working in "sensitive" jobs such as airports - and again the employees will need the document to go about their business.
The Home Secretary says these workers will benefit from a card that guarantees their identity - but conceded at the foreign ID card that airport staff already face more security checks than those required for the national scheme.
Opponents say this all smacks of a "softening up" exercise for the general population.
They accuse the government of incrementally chipping away at opposition by slowly bringing everyone in to the register over a decade, without having to win a debate over its actual merits.
People with the least power to complain are being used as "guinea pigs" for an untried and controversial system.
No 'magic bullet'
The Home Office says the foreign national card has many practical purposes.
It argues the card is a positive thing for the migrant - an easy way to assert one's identity and acceptance into British society.
But there are also an awful lot of migrants living and working without permission in the UK.
Critics say the card is no magic bullet for people who are invisible - people who survive in the black economy working for people who don't care about doing things by the book.
The Conservatives have raised no objections to collecting biometric identity data on foreign nationals. But they object fiercely to the idea of a national identity register because they believe it is neither workable nor needed.
So while the Home Office pushes ahead with the £4.7bn scheme, its survival may hinge on the outcome of the next general election.
But here's another thought.
Officials confidently predict that every new immigrant will be given a card within three years - and that nine out of 10 foreign nationals already in the UK (legally) will be in the scheme by 2015.
We've never had a reliable figure for how many people come and go each year - which means that public tension over migration is based on only half the picture.
All those biometric records beeping away at airports may soon help to answer those questions once and for all.