Secrets revealed by dirty books from medieval times
The reading habits of medieval people have revealed details of their lifestyle, in research carried out at St Andrews University.
Researchers have found them to have many characteristics still found in modern readers.
They said medieval people feared illness, were selfish and often fell asleep while reading late at night.
The work used a technique developed by Dr Kathryn Rudy, which measures the dirt accumulated on medieval manuscripts.
Dr Rudy, a lecturer in the School of Art History at St Andrews, realised that the dirtiest pages are likely to have been the most read.
A machine called a densitometer was used to reveal the dirt contained within the pages of books.
One of the dirtiest pages in a selection of European religious books was a prayer to St Sebastian, who was often prayed to because his arrow-wounds - the cause of his martyrdom - looked like the bubonic plague.
This indicated that the reader of the book was terrified of the plague and repeated the prayer to ward off the disease.
Pages which contained the prayers for the salvation of others were less dirty than those asking for salvation for oneself.
As well as demonstrating medieval people prayed for their own assistance, the analysis showed the pages of a prayer to be said in the small hours of the morning were only dirty for the first few pages.
It has been suggested this shows most readers fell asleep at the same point.
Dr Rudy said: "Although it is often difficult to study the habits, private rituals and emotional states of people, this new technique can let us into the minds of people from the past.
"Religion was inseparable from physical health, time management, and interpersonal relationships in medieval times.
"In the century before printing, people ordered tens of thousands of prayer books - sometimes quite beautifully illuminated ones - even though they might cost as much as a house.
"As a result they were treasured, read several times a day at key prayer times, and through analysing how dirty the pages are we can identify the priorities and beliefs of their owners."