Shadowy traces of these ancient highways – the most famous of which is known as Sarn Helen – can still be seen (you’ll need an Ordnance Survey map, not sat nav, to find them).
Mae olion rhithiol y priffyrdd hynafol hyn - a’r enwocaf ohonynt yn cael ei galw’n Sarn Helen - i’w gweld o hyd (bydd angen map Arolwg Ordnans, nid Sat Nav, arnoch i ddod o hyd iddynt).