There’s not much in the way of evidence that The Templars made inroads into Wales. They are very much associated with the Normans and the Holy Land … not that Welshmen didn’t go on Crusade, because many did, but that the institution didn’t attract much of a following among the native Welsh.
“In 1156 the Countess of Warwick gave the Templars the church of Llanmadoc in the Gower, and until the early 1280s they held Templeton in Pembrokeshire – contemporary documents call it “Villa Templar”, “Templars’ village”.
The famous William Marshal may have given them the mill they owned outside Pembroke castle, and he may have been the donor who gave them the church of Kemeys Commander on the River Usk.
The Templars were also given small parcels of land in Glamorganshire and Gwent.
But although the Templars received extensive properties in Herefordshire and Shropshire, in the Welsh March, the Welsh did not donate to the Templars.
In contrast, the Welsh in Pembrokeshire and Gwynedd did donate to the Hospitallers. The Hospitallers’ house at Slebech on the Eastern Cleddau river was given to them by a Flemish family who had settled in the area, and supported by donations from Normans, Welsh and English alike.
Slebech became an administrative centre or commandery, the Hospitallers’ fourth richest commandery in England and Wales.”
The Hospitalliers, in contrast to the Templars, did not provoke the ire of the French king and continue to this day. They were founded at about the same time as the Templars, in order to care of the sick in the Holy Lands.
“One of the most powerful political organizations in the late Middle Ages was the Order of St. John of Jerusalem, the Knights Hospitallers, whose ranks were filled by scions of the richest aristocratic families of Europe. Formed in Jerusalem in the 11th Century to provide hospital care and protection to Christian pilgrims visiting the Holy Land, the Knights soon became one of the foremost military powers in the region. Their base of operations was a chain of castles and ports. After Saladin, King of the Saracens, dislodged them from Jerusalem, the Knights relocated briefly to Cyprus, and then to the island of Rhodes in 1309.” http://www.rapidappsgroup.com/history
The preceptory of Halston “was founded between 1165 and 1187, when Roger de Powys, lord of Whittington, granted the Hospitallers a portion of his demesne. By the second decade of the 13th century it was sufficiently well established to be considered by the bishop of St. Asaph a suitable guardian for his hospital at Oswestry …
By 1294 the preceptory of Dolgynwal (Yspytty Ifan, Denbighs.) had been united with Halston, which was subsequently the administrative centre for all Hospitaller estates in north Wales. Dolgynwal, which had been founded c. 1190, had acquired Ellesmere church, its most substantial property, from Llywelyn the Great in 1225. Its estates also included the chapel of Penmachno (Caern.) and presumably Gwanas grange (Merion.), since this also lay in Gwynedd. Of the three remaining properties in north Wales later administered from Halston the church of Tregynon (Mont.) already in part belonged to Halston by 1254 …” http://www.british-history.ac.uk/report.aspx?compid=39933
For $112 you can get “A History of the Order of St. John of Jerusalem in Wales and on the Welsh Border: Including an Account of the Templars”: http://www.amazon.com/exec/obidos/ASIN/0404154271/britigrandprioro