The ruins of Launceston Castle still dominate the old market town, and act as a constant reminder of the former authority that the Earls of Cornwall wielded over the local inhabitants. As an administrative centre, Launceston Castle maintained huge estates and was responsible for the collection of rents, as well as controlling the main route into Cornwall.

In the latter part of the 11th century, the first Norman castle was constructed, probably of timber, and surrounded by a good defensive system of ditches. However, very few factual details are known about the castle until the time of Richard of Cornwall, who held the earldom from 1227 to 1272. Being one of the wealthiest and most powerful men in the Kingdom at that time, Launceston Castle underwent a major rebuilding programme to reflect his status.

The imposing, solid drum towers either side of the South Gatehouse, and the re-siting of the North Gate (or Town Gate) were part of Richard's work, along with the circular, high tower inserted in the shell Keep. In fact, it would appear that he became over zealous with improving the defences at Launceston Castle, yet there would have been little military threat at that time. Furthermore, from excavation works, it seems that the once, tightly-packed buildings in the castle bailey were completely levelled and replaced by a Great Hall with an adjoining kitchen, and a small chapel.

Following Richard's death, Launceston Castle's fortunes suffered and, consequently, it suffered a period of neglect. In 1341 repairs commenced, and seem to have continued well into the 15th century. The Great Hall remained in use until the early 1600s as the County Assizes, and the North Gatehouse became an infamous prison. Only a few decades later, when the Parliamentary Survey of 1650 was conducted, the Hall had been demolished. From the middle of the 18th century, Launceston Castle saw many changes - most of the remaining buildings were demolished, the grounds were landscaped and turned into a public park by the Duke of Northumberland and, almost as a final insult, the interior of the bailey was littered with wartime huts.

Having been subjected to such a turbulent past, been associated with gruesome executions, and been virtually destroyed on numerous occasions, it is with some relief that the visitor today can enjoy a peaceful stroll around these much restored ruins.