Polson Bridge is one of the reasons why both Lanstephen and Launceston developed where they did. For much of its length the River Tamar forms a formidable natural barrier between Cornwall and Devon, but at Polson there was an important crossing point that could be depended upon when many other crossings became impassable. Long before the construction of the modern bridge, travellers heading into Cornwall naturally converged upon this location. Merchants, pilgrims, officials, judges, armies and ordinary travellers all found themselves funnelled towards the same narrow point. The strategic significance of the crossing was therefore recognised by successive generations, from the Saxons who established Lanstephen to the Normans who later constructed Dunheved and Launceston Castle on the commanding heights overlooking the surrounding countryside.
The importance of the crossing increased during the medieval period. A bridge had been established here by the twelfth century, removing much of the uncertainty associated with crossing the Tamar and helping to strengthen communications between Cornwall and the rest of England. The route passing over Polson Bridge connected Launceston with Exeter and beyond, making it one of the principal gateways into the county. The wealth of Launceston depended heavily upon this route. Merchants bringing goods into Cornwall and exporting Cornish produce out of it would often pass this way. The crossing was also important to the administration of justice. Launceston was the county town of Cornwall for much of the medieval period and judges, officials and royal representatives regularly crossed the bridge on their way to and from the town.
The nearby leper hospital of St Leonard's owed part of its existence to the bridge. The hospital stood only a short distance from this busy route and its occupants were able to seek alms from the constant flow of travellers. Medieval Christianity placed a strong emphasis upon charitable giving and there were few more effective places to solicit donations than one of the principal crossing points into Cornwall. The strategic location that benefited merchants and officials therefore also benefited some of the poorest and most vulnerable people in medieval society.
The bridge played an equally important role during periods of unrest. Cornish rebels heading east during the rising of 1497 are believed to have crossed the Tamar here on their march towards London. The route would again have witnessed military movement during the Prayer Book Rebellion of 1549 when thousands of Cornishmen marched eastwards in protest against religious changes imposed by the government of Edward VI. Whilst the bridge itself was not the focus of these rebellions, anyone moving a large force between Cornwall and Devon was almost certain to take account of one of the county's most dependable crossings.
Its greatest military significance came during the English Civil War. In 1643 Parliamentarian forces under Major-General James Chudleigh crossed into Cornwall and advanced towards Launceston in an attempt to challenge the Royalist dominance of the county. Fighting developed around Beacon Hill overlooking the town and for a time the Parliamentarian attack appeared to be succeeding. As Royalist reinforcements under Sir Ralph Hopton arrived, however, the situation changed dramatically. Chudleigh's men were forced into retreat towards the Tamar. The importance of Polson Bridge suddenly became obvious. Control of the crossing meant the difference between an organised withdrawal and a disastrous rout. Fortunately for the Parliamentarians, reinforcements including the famous London Greycoats reached the bridge in time to secure it. This allowed Chudleigh's battered army to retreat back into Devon and prevented what might otherwise have become a catastrophic defeat.
Polson Bridge reappeared in military planning during the final stages of the Civil War. As Fairfax and the New Model Army advanced into the West Country, Cornwall became one of the last major Royalist strongholds. The control or destruction of strategic river crossings became increasingly important as Parliament sought to prevent Royalist forces from manoeuvring between Cornwall and Devon. Whether carrying traders, judges or soldiers, the bridge remained one of the key tactical points on the eastern approaches to Cornwall.
Although modern travellers often cross Polson Bridge without giving it a second thought, its importance endured well beyond the Civil War. Coaching traffic, commercial wagons and later motor vehicles all continued to use the same route because the geography of the Tamar valley had not changed. The bridge has been rebuilt and modified numerous times over the centuries, yet it still performs precisely the same function as its medieval predecessor. Just as Saxons, Normans, merchants, lepers and Civil War soldiers once depended upon the crossing, modern traffic continues to funnel through the same strategic gateway. Few places illustrate so clearly the enduring importance of geography. Governments, kingdoms and political systems have all changed repeatedly, but travellers still cross the Tamar at Polson just as they have done for centuries.
