The York-based Borthwick Institute, founded in 1953 with a bequest from Bridlington perfumier William Borthwick, is one of the country's leading archives, holding thousands of documents.
They range from the Earl of Halifax's family archives to Charl
otte Brontë's will to records of William Wordsworth's wedding in Brompton-by Sawdon, near Scarborough.
Now the institute is helping people to research their family trees by providing online copies of 35,000 York wills and related records via a family history website.
The last testaments have already revealed some bizarre states of mind among those contemplating their deaths.
Land used to pass down through the family until the Statute of Wills in 1540, when the owner could bequeath land to whomever he wished.
Before 1540 it was possible to bequeath possessions other than land, for example money, through a written testament.
In 1464, John Smyth was so afraid of being murdered by Robert Lee that he left money to bring his enemy to justice if he died.
Thomas Beauchamp, a chaplain of Hull, had mortality on his mind when he made his will talking about the "particularly dangerous time of pestilence". He became a casualty soon after.
Although it is no surprise many people thought about giving money to charities, not all were what would be thought of as good causes today. Some looked beyond their own deaths and families to distant parts and obscure causes. In 1429 John Pigot, a knight, left money for the fight against heretics in Bohemia.
Their wills are among 35,000 probate records, the largest collection in England outside London, being made available by the Institute on the British Origins Network website, www.britishorigins.com
When anyone leaves a will, a process known as grant of probate must be carried out so that the will is proved or made valid.
Until 1858, probate was granted in the church court which had jurisdiction over the area in which a person's property or possessions lay.
The Prerogative Court of Canterbury was the most important of these courts. But for information about ordinary people, many historians have headed for the Yorkshire archives.
Despite often being in Latin, wills provide vital information for family trees.
Many of those being published online have come from the York Medieval Probate Index of more than 10,000 wills proved in the Prerogative and Exchequer Courts of York from 1267 to 1500. The rest come from the York Peculiars Probate Index 1383-1883, covering more than 25,000 wills formally approved in the 54 "peculiar", or special, courts of the Province of York from 1383 to 1883.
While the great majority of the documents relate to persons with property in Yorkshire, 12 per cent refer to every county in England, plus Ireland, France, Poland, Scotland, and Wales.
The Origins Network includes marriage registers, wills, census returns, valuation records, court and apprentice records, as well as place-related images such as original survey maps.
Managing director Ian Galbraith said: "The network partners with the foremost British and Irish institutions to provide online access to some of the richest genealogy collections anywhere.
"We are very proud to be selected as the exclusive provider of the Borthwick Institute's records online."
The institute last summer moved to a purpose-built archive at Heslington, next to the University of York's JBM Library.
mark.branagan@ypn.co.uk
