In 1068, two years after the Norman Conquest, there was a rebellion in the South-West. It was put down by King William, following which Launceston and Trematon Castles were constructed in order to exercise greater control over the area. A barony was assigned to each of these castles.

The Trematon barony comprised some 60 manors, situated mostly in SE Cornwall and. SW Devon. By 1086 a market had been established outside the main gate of Trematon Castle. The lord, Reginald de Valletort I, followed this up by founding a borough adjoining the castle. In those unsettled times, a borough needed the close protection which a castle provided. Later, from 1139 until 1153. there was civil war. Following the accession of King Henry II in 1154, stability was gradually achieved.

Eventually the then de Valletort lord realised that the borough at Trematon Castle would never prosper because the site was poorly positioned for trade. So he decided to found a new borough adjoining the ancient ferry across the Tamar estuary at Esse (the Middle English form of Modern English Ash, meaning ash tree). That was an excellent location for commerce - a place where a major land highway crossed a water highway.

On the hillside above the original small waterside community (which was absorbed), new streets and a market square were set out to the north of the existing ferry access route (which today, for the most part, is Culver Road) and more than a hundred building plots were laid out.

People were invited to settle in the new borough for a small annual burgage rent (thus avoiding the heavier manorial dues and obligations which applied outside it) and so become burgesses. It was a process which went on all over the country for 250 years and is dealt with thoroughly in Prof. Maurice Beresford's classic book, New Towns of the Middle Ages.

As a further incentive, at the outset the de Valletort lord had a large chapel built adjoining the market square. (At that period, the naves of churches and chapels were used on weekdays as community halls.) Appropriately, the chapel was dedicated to St Nicholas, patron saint of (among other things) travellers, sailors and safe journeys. Ecclesiastically, it was subordinate to the parish church at St Stephens.

As no borough foundation charter has survived, to some extent the architectural evidence provided by St Nick's has to be used to determine a date. Thus circa 1175 is the best estimate for the foundation of the borough. This means that the founder was either Ralph de Valletort I, who died in 1172, or Reginald II who then succeeded him.

Much of that Norman chapel-of-ease still exists. A north aisle was added to it in the C15. After the Reformation, Saltash Corporation claimed ownership of the building - a claim not finally given up until 1923! It became the parish church for the area of the old borough in 1.881.

At first, the borough's annual Fair was held in the market square, but later (perhaps by 1337, certainly before 1435) it was moved to the outskirts of the town. Livestock sales were an important element of medieval fairs, so a spacious site away from dwellings was obviously better. A chapel was erected alongside the new fair-place. It was dedicated to St Faith, the 6th October (St Faith's Day) being the last day of the fair. St Faith's Chapel was closed at the Reformation. but its walls remained for another 250 years or so. It stood roughly where Regal Court adjoins Fore Street today.

The first known charter was granted by Reginald de Valletort III to his burgesses of Essa circa 1225 (like many early seigniorial charters, it wasn't dated). In it he confirmed all the privileges which they had in the time of his ancestors. (The spelling Essa occurs only in this document; it is a phonetic rendering of Esse.) Incidentally, Reginald III was involved in national affairs. At the age of just 21, he was a signatory to the first reissue of Magna Carta in 1216. He was Sheriff of Cornwall in 1225.

The new market town at Ash prospered, and also became a port. Around 1300 the prefix Salt- was added to its name, although not consistently at first. This was done to distinguish it from the dozen or so places in Devon having the same name (many of them also acquired prefixes or suffixes).

(A small borough continued at Trematon Castle throughout the medieval period. It still existed in name at least, as late as 1650.)