OLD KNUCKLAS
There are some local pictures in the Knucklas/Heyope archive at The Peoples Collection, Wales, collected by a Knucklas man. Look here: 
There is some useful information in Wikipedia here:
CPAT (Clwyd Powys Archaeological Trust) have information here:
There are fascinating extracts from documents of 1833 and 1868 about Knucklas, Heyop, and Beguildy here:
The most famous person from Knucklas is probably Vavasor Powell, a Welsh Puritan preacher in the 17th Century.
Biographies can be found here: and here:
If anyone has any old photographs, documents or just memories of the old days, we would love to hear from you. Use the form on “Contact us” page or call 520266.
KNUCKLAS CASTLE
Information about the castle is available in several places:
The castle hill as a possible iron age fort is noted here:
Our own Knucklas Castle Community Land Project – click to visit:
Paul Remfry has published his understanding of the castle here: and here:
Some minimal information is here (with the wrong directions!):
The Mortimer Society have, of course, a great interest in the history of the area and much information; look here:
The Luminarium also has references; look here:
The Arthur and Guinevere legend appears in many places. For instance King Arthur’s Knights site here:
also the Britannia (USA) site:
Also the Early British Kingdoms site has much information here:
THE VIADUCT
The famous viaduct is often mentioned by historians and railway enthusiasts. It is a listed building grade II* and listing details are here:
The transport Heritage site has some good information: ; and Wikipedia (see link above) has some limited information.
The viaduct was completed in 1863 by the Central Wales Railway, and the line was opened in 1864. It is 190 yards long and consists of 13 arches and is 75 feet high. Its major features are the castellated towers at either end and the embellished parapets. Then the line southwards rises at 1 in 60 (the steepest part of the line) to the highest point of the line at 320m (980ft) as the line leaves the Llangunllo tunnel.
HOWLTA have produced a small pamphlet to celebrate the 150th anniversary of its opening: see here and here Viaduct history
A good video on YouTube shows steam hauled train on the viaduct:
THE RADNORSHIRE SOCIETY
The Radnorshire Society have an interest in all Radnorshire history and their web site is here:
ST. DAVID’S CHURCHYARD
The Knucklas Castle Community Land Project initiated a survey of the graves in St. David’s church, Heyope.
The results are available on the church web site here:
Anyone looking for history of families in the area may find something useful there.