A writing tablet found in the mud. (Photo: MOLA)

Romans were businesspeople, and when they founded London in the 40s—in the first half of the first century A.D.—they were busy trading, lending, and generally making money. Naturally, the writing tablets that turned up in what’s been called “London’s single largest archaeological excavation of all time” document financial transactions.

One, the earliest dated document ever found in Britain, has a freed slave named Tibullus promising repayment of 105 denarii, a hefty sum, to another freed slave, Gratus.

Tibullus made that promise on January 8, 57.

These tablets, more than 400 in all, were found in what the Guardian calls “a sodden hole” under a 1950s office building, the future site of a fancy new Bloomberg headquarters in London. Eighty-seven of the tablets have been deciphered so far, and they include the first ever written reference to London.

The first written mention of London. (Photo: MOLA)

The tablets also include evidence of writing practice, an admonishment from one friend to another that he’s lent too much money and is being gossiped about, and a plea for repayment. These tablets were made of recycled barrel staves, National Geographic notes, and would have been covered in black beeswax, to make the writing legible. When they were found in the mud, they were kept in water, before being cleaned and freeze-dried for preservation.

The marks that were left on the wood were faint scratches of a stylus that had poke through the beeswax. To read the messages preserved on the wood, researchers had to take digital photographs of the tablets from multiple angles, then overlay them so that the marks would emerge more clearly.

The short messages that have been deciphered help corroborate other sources containing details about London’s early history, and in one case, correct the date of an important rebellion by a tribe native to the island, which burned the city down. London rebounded.

Bonus finds: Spiky tomato that looks like it’s bleeding, 40 dead tiger cubs in a freezer

Every day, we highlight one newly found object, curiosity or wonder. Discover something amazing? Tell us about it! Send your finds to sarah.laskow@atlasobscura.com.