In July they made hay as we do and in August they harvested. The difference came in September and November when they slaughtered cattle and pigs in the open, with children looking gaily on and a woman catching the blood in a pan.

These naturalistic but exquisitely painted glimpses of seasonal life nearly 500 years ago are expected to fetch as much as £1m at auction in London on Mon day - partly because the images are only 2.5in tall and less than 1.75in high.

They come from what is believed to be the tiniest work created by Simon Bening, the Flemish master illuminator. This is a 216-page book of hours made with initial letters of liquid gold between 1530 and 1535, probably for the Portuguese royal family.

Books of hours began to appear in the 13th century. They were carried as jewellery around the neck or hung from a girdle so that prayers could be said at the correct time in the Christian calendar.

Christie's specialists say the book's "mastery of landscape and delight in different light effects... suggest that this manuscript was made by Bening as a demonstration of his supreme technical mastery and artistic sensibility".