Two notes with the same serial number

In the British Museum in London, two Portuguese 500 Escudo notes are placed side-by-side. They are from the year 1922. The upper one is stamped with DUPLICADO—duplicate, and has been invalidated. The lower one is a legitimate note.

Both notes have the same serial number: 1K 02201.

A forgery without engraved plates

In 1925, a man named Alves dos Reis made his move. He did not engrave plates or imitate the paper. Instead, he created a forged letter of authorization and ordered the printing of banknotes from a printing company in London.

The company believed it was a legitimate order and printed them: with the real plates, on the real paper, using the official process. The printed banknotes were then transported to Portugal without authorization.

They were indistinguishable. Naturally. Because the same company had printed them with the same plates.

Where authenticity resides

So, is this a counterfeit note?

As an object, it is genuine. In terms of authority, it is counterfeit. The authenticity of currency does not lie with the paper. It lies in a single point: who authorized its issuance.

The paper and plates were genuine; the only thing missing was the authority to issue.

The inscription (the text printed on banknotes and coins) would also tell you that this note is genuine. The only place the answer changes is in the issuance ledger.

What the incident destroyed

After the scheme was exposed, the credibility of the Bank of Portugal was severely damaged. The task of determining how many notes had entered circulation proved difficult. People began to doubt whether the paper in their hands was genuine.

Compounded by political turmoil, the military staged a coup d'état the following year, 1926. The credibility of the currency was contiguous with the credibility of the government.

However, the extent to which a direct causal link can be drawn between the incident and the political upheaval has not been established. The figures for the amount that entered circulation also vary by source, so they will not be cited here. What is certain is the single fact that the two notes bear the same number.

Exhibition as a counterargument

These two notes are displayed openly. This is because showing the counterfeit alongside the genuine best explains what currency is.

If the thing that separates genuine from counterfeit does not lie in the material, then it lies in the system. The system is invisible. To make the invisible visible, the two notes were placed side-by-side, sharing the same number.