As you cross the bridge, look up river to your right. The medieval bridge, Leland’s ‘Pont yr Hesg’, was probably on about the same line as the Taff Vale Railway bridge in front of you. Craig yr Hesg is the rocky outcrop above the west bank of the river. The same rock strata outcrop across the river, making the rapids and small waterfalls you can see under the railway bridge. The rocky outcrops would also have provided the footings for the medieval bridge.
Leland said that all the bridges in this area were made of timber. As he explained, ‘the water ... cometh so down from woody hills, and often bringeth down such logs and trees, that the country were not able to make up the bridges if they were stone, they should be so often broken’. Stone bridges would have had to be supported on piers on the river bed, but a timber bridge could be slung across from outcrop to outcrop and could be replaced easily and cheaply if it was damaged.
Leland listed a number of bridges in the Taff and Rhondda valleys. As well as Pont yr Hesg, there was a bridge on the Rhondda Fach below Penrhys, presumably on the line of the modern Pontygwaith at about ST 009 945. We cross a modern bridge on the same site later in this route. Leland also mentioned bridges on the Rhondda Fawr ‘one of wood a quarter of a mile west from Penrise. Pont Kemmer [Pontycymmer, ‘bridge of the confluence’] a 2 miles lower, and a little beneath is the confluence’, another bridge on the Rhondda Fach ‘a little above the confluence right against the bridge on Rhondda Fawr’ and ‘a bridge of wood on the whole Rhondda called Pont Newith [Pont Newydd, ‘new bridge’] 2 miles beneath the confluence and a quarter from the place where it goeth into Taff’.
These bridges were all in good order in 1540. But by the time Rice Merrick described the area about 40 years later, the bridges on the Rhondda had apparently vanished and Pont yr Hesg was ‘decayed’. It seems most likely that the bridges had been maintained for the benefit of pilgrims to Penrhys. The task would almost certainly have been beyond the resources of the local population, and the money probably came from Llantarnam. When the monastery was dissolved and the shrine dismantled, there was no-one with the organisational skills to maintain the bridges, and they soon decayed. This was a loss to the local community. The rivers are deep in places and fast flowing, and it would have been a long walk up river to a point at which they could be forded in winter.