Who would imagine that sheepskin can play a role in politics. A new study has shown how lawyers in the medieval era used sheepskin to prevent corruption. From Science Daily:

Experts have identified the species of animals used for British legal documents dating from the 13th to 20th century, and have discovered they were almost always written on sheepskin, rather than goatskin or calfskin vellum.

This may have been because the structure of sheepskin made attempts to remove or modify text obvious.

Sheep deposit fat in-between the various layers of their skin. During parchment manufacture, the skin is submerged in lime, which draws out the fat leaving voids between the layers. Attempts to scrape off the ink would result in these layers detaching — known as delamination — leaving a visible blemish highlighting any attempts to change any writing.

Sheepskin has a very high fat content, accounting for as much as 30 to 50 per cent, compared to 3 to 10 per cent in goatskin and just 2 to 3 per cent in cattle. Consequently, the potential for scraping to detach these layers is considerably greater in sheepskin than those of other animals.

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