Mae Aber Hafren wedi bod yn rhwystr i deithwyr rhwng Cymru a Lloegr ers yr amseroedd cynharaf

        The Severn Estuary has been an obstacle for travellers between Wales and England since earliest times

Croesodd milwyr Rhufeinig yr Hafren mewn cwch o Aust, ger Pont Hafren bresennol

         Roman soldiers crossed the Severn by boat from Aust, near the present Severn Bridge

Yng Nghanol Oesoedd, defnyddiwyd yr un man croesi gan fynachod Abaty Tyndyrn

         In the Middle Ages, the same crossing point was used by the monks of Tintern Abbey

Yn y bedwaredd ganrif ar bymtheg dechreuodd fferi stêm, ac adeiladwyd ceiau ar y ddwy lan

         In the nineteenth century a steam ferry began, and quays were built on both banks

Adeiladwyd pont reilffordd ym 1879, dilynwyd gan dwnnel rheilffordd Hafren ym 1886

         A railway bridge was built in 1879, followed by the Severn railway tunnel in 1886

Collodd y gwasanaeth cychod stêm ei draffig, a chaeodd y gwasanaeth

         The steam boat service lost its traffic, and the sevice closed

Roedd pont reilffordd Hafren yn draphont hir gydag un ar hugain o rychwantau yn cael eu cynnal ar silindrau haearn

         The Severn railway bridge was a long viaduct with twenty one spans supported on iron cylinders

Roedd y bont yn cludo trenau o fwyn haearn a glo o gloddfeydd yn Fforest y Ddena

         The bridge carried trains of iron ore and coal from mines in the Forest of Dean

Parhaodd y bont i gael ei defnyddio tan 1960 pan fu dwy long, oedd yn cludo tanwydd, mewn gwrthdrawiad, yna eu tarodd y bont yn achosi ffrwydrad

         The bridge continued to be in use until 1960 when two ships, which were carrying fuel, collided and then struck the bridge, causing an explosion

Byddai`r atgyweiriadau i`r bont wedi bod yn rhy ddrud, felly cafodd ei dymchwel

         Repairs to the bridge would have been too expensive, so it was demolished

Pan adeiladwyd Twnnel Hafren, hwn oedd y twnnel rheilffordd hiraf ym Mhrydain

         When the Severn Tunnel was built, it was the longest rail tunnel in Britain

Cafodd y peirianwyr broblemau enfawr gyda dŵr yn llifo i`r twnnel o`r graig o`i amgylch

         The engineers had huge problems with water flowing into the tunnel from the surrounding rock

Mae`r twnnel yn dal i gludo`r rheilffordd o Fryste i Dde Cymru

         The tunnel still carries the railway from Bristol to South Wales

Mae angen pwmpio yn barhaus i`w gadw`n sych

         Continual pumping is required to keep it dry

Wrth i draffig modur yn cynyddu, ailagorwyd y gwasanaeth fferi ym 1926

         As motor traffic increased, the ferry service was re-opened in 1926

Roedd y fferïau bach yn gallu cario tua ugain o geir

         The small ferries were able to carry about twenty cars

Cafodd yr amrediad llanw enfawr effaith ar amserlen y fferi

         The huge tidal range affected the ferry timetable

Nid oedd y cychod yn gallu gweithredu ar lanw isel nac ar lanw uchel iawn

         The boats were unable to operate at low tide or at very high tide

Caeodd y fferi ym 1966 pan agorodd Pont Hafren gyntaf

         The ferry closed in 1966 when the first Severn Bridge opened

Mae`r bont grog enfawr hon yn cario`r draffordd

         This huge suspension bridge carries the motorway

Dilynwyd hyn gan adeiladu Ail Groesfan Hafren, adnabyddir hefyd fel Pont Tywysog Cymru

         This was followed by construction of the Second Severn Crossing, also known as the Prince of Wales Bridge

Hyd at fis Rhagfyr 2018, roedd yn rhaid i yrwyr dalu toll i groesi`r naill neu`r llall o`r pontydd, ond ni chodir tollau mwyach

         Until December 2018, drivers had to pay a toll to cross either of the bridges, but tolls are no longer charged