The registers contains eight million entries in Wales
Local parish records dating back to the 16th Century are to be published online as part of a Wales-wide project.
And visitors to Powys Archive at Llandrindod Wells will be able to access the data free-of-charge.
Entries include executions of people for horse and sheep stealing and the death of a Llanfihangel Cwm Du man who sat on a toad.
The free facility for people living in Powys can also be accessed at Brecon and Newtown libraries.
The project is taking place with the permission of the Church in Wales and Welsh Archive Services and will be made available over the next two years.
They will be working with family history website
and FamilySearch International, the world's largest repository of genealogical records, to digitise the records.
Around 893,000 images containing eight million baptisms, marriages and burials from across Wales will be filmed by FamilySearch and transcribed by findmypast.co.uk.
Some of the records date back to the 16th Century, making it possible to find Welsh ancestors as far back as the 1500s.
The records contain entries in English and Latin.
Catherine Richards, the County Archivist at Powys and Chair of the Welsh County Archivists' Group, said: "We are very excited to make our parish registers available online.
"Records of baptisms, marriages and burials are a major resource for family historians and can reveal fascinating and surprising secrets back through the generations.
"Often comments were added by the incumbents about illegitimacy, cause of death or other interesting facts."
For example, on 8 Sept 1775 the Llywel parish register makes a record of an earthquake in the middle of the night.
The entry reads 'across Britain this earthquake was reported as far as Devon, Oxford, and Lancashire - in Swansea some houses were said to have tumbled in'.
Death by toad
In the Llanfihangel Cwm Du registers of the early 19th Century the cause of death is recorded.
For example, on 16 Sept 1809, John Andrews, 'died of a mortification in his privities in consequence of his having sat on a toad'.
Other entries include those of the deaths of John Jones of Kerry in 1814 after fighting in a churchyard; John Llwarch of Presteigne who was executed for horse stealing; Elizabeth Davies of Presteigne, who was executed for stealing sheep; and John Ford of Llanhamlach, who died after a gaming table incident.
Findmypast.co.uk was the first company in the world to put the complete Birth, Marriage and Death indexes for England and Wales online in April 2003.
Previously these were only available offline on microfiche or in registry books, at a selected number of locations.