“The Palace of Westminster burned down because someone was too lazy to find a better way to dispose of old database records. Katie's Law has been operating since 30,000 BCE.”
The Device
A tally stick is a piece of bone or wood — willow was common in medieval England — with notches cut into it to record a number. The notch size indicated magnitude: a V-shaped notch indicated one pound, a larger notch indicated five pounds, a fully separated notch indicated twenty, and so on. The encoding is positional and unambiguous.
The critical innovation: after the notches were cut, the stick was split lengthwise. The creditor kept the longer piece (the "stock" — origin of the word "stockholder"). The debtor kept the shorter piece (the "foil"). A genuine tally could be verified by matching the two halves: if the grain and notches aligned perfectly, the record was authentic. If someone carved their own stick, the grain would not match. This is a cryptographic tamper-evident ledger made of wood.
The earliest known tally sticks — the Lebombo and Ishango bones — are 30,000 to 40,000 years old. The notch encoding is identical to the principle used in much later counting devices. Humanity developed this abstraction once and used it continuously for thirty millennia.
The British Exchequer's Tally System
From approximately the 12th century, the British Exchequer used tally sticks as official financial instruments. Tax receipts, loans to the Crown, government debt — all recorded on willow tallies and split between the Crown and the counterparty. The Bank of England accepted tally sticks as payment against tax obligations into the 19th century.
Parliament abolished the tally stick system in 1826, replacing it with paper ledgers. This was a sound architectural decision — paper scales better, is easier to copy, and doesn't require a physical asset for each record. The accumulated sticks were kept in storage while the administrative transition completed.
The Disaster
In October 1834, a subordinate of the Exchequer decided to dispose of the accumulated sticks. The approved method was to burn them. The decided location was the furnace beneath the House of Lords.
The furnace was too small for the volume of sticks. The operator loaded it repeatedly. The excess heat spread through the flue system. At 6 PM on October 16, 1834, workers noticed smoke rising from beneath the House of Lords chamber. By midnight, the Palace of Westminster — the seat of British Parliament, built in the 11th century — was destroyed. The House of Commons and the House of Lords were burned to the ground.
The current Palace of Westminster — the Victorian Gothic building famous for Big Ben — was built as the replacement.
The Pattern
The tally stick disaster is Katie's Law operating at 700-year timescale: the deferred decision (what do we do with the old records when we migrate systems?) was answered with a shortcut (burn them in the nearest available furnace) that caused a catastrophic irreversible failure (a thousand-year-old building burned down).
This is also [The Dead Branch](/exhibits/the-dead-branch): legacy data that nobody knows how to handle, kept in storage because disposing of it is someone else's problem, until someone makes it their problem in the worst possible way.
Every time you let deprecated data, old migrations, or legacy database tables accumulate because "we'll deal with it later" — you are storing tally sticks in a furnace room. Parliament learned this in 1834. The lesson is documented here.