Located in the city of Lincoln, which by Norman times, rated third in prosperity and importance of the cities in England. Something that was due to its location and proximity of roads and rivers. Following the defeat of the English by William Duke of Normandy (William the Conqueror) at the Battle of Hastings in 1066, William encountered resistance to his rule particularly in the North of the country and wished to consolidate his position; one such way of doing this was to construct a number of castles. In 1068 he commenced the construction of Lincoln Castle on the site of the former Roman fort at the top of the hill. This construction covered part of the Roman wall and has recently found to have been built over a stone church dating back to the Anglo-Saxon period. The construction of the castle was to involve the demolition of some 166 houses.
William’s castle would have been constructed of wood, this was virtually destroyed by fire in 1113 which resulted in it being replaced by a stone construction. Lincoln Castle is bounded by stone walls, with ditches on all sides except the south. On the south side the walls are interrupted by two earthen mounds called mottes. Lincoln Castle is very unusual in that it has two mottes. To the south, where the Roman wall stands on the edge of a steep slope, it was retained partially as a curtain wall and partially as a revetment retaining the mottes. In the west, where the ground is more level, the Roman wall was buried within an earth rampart and extended upward to form the Norman castle wall. Excavation work was carried out in the 19th century on the Westgate (which concealed the Roman Westgate) which had been buried but this resulted in it becoming unstable so the work stopped and it was re-buried.
The Westgate was the main entrance in medieval times and would have led into open countryside through the city wall, but it was sealed up, possibly in the fifteenth century and has only recently been reopened.
One of the mounds is in the south east corner, and was probably an original feature of William's castle, while the other occupies the south west corner. A square tower stands on top of this mound, standing above the outer walls to dominate the city. The second mound is crowned by the 'Lucy Tower', which is thought to have been built in the 12th century and named after the Lucy of Bolingbroke, the Countess of Chester.
The castle was the focus of attention during the First Battle of Lincoln which occurred on 2 February 1141, during the struggle between King Stephen and Empress Maud over who should be monarch in England. The castle held but suffered damage which necessitated rebuilding.
The Castle was again the site of a siege and the subsequent Second Battle of Lincoln which occurred in the course of the First Barons' War (1215–17) . This was the period of political struggle which led to the signing of Magna Carta on 15 June 1215. After this, a new barbican (a fortified outpost or gateway) was built onto the west and east gates.
The castle contains a number of towers, the Lucy tower is the15-sided shell keep built on the larger motte, this was named after the mother of a 12th century owner, Lucy, Countess of Chester. The tower is an open structure but would probably have contained lean-to buildings against the inner wall. This medieval keep later became the Victorial burial ground for convicts.
The Observatory Tower is square in plan and built on the smaller motte at the south east corner. Part of the tower is Norman, with 14th century adaption’s with an observatory being added in the 19th century by the then governor of the prison which gave it its’ name.
The East Gate is the main entrance to the castle and was originally a plain Norman arch built into a rectangular recess in the wall. In later years it was strengthened by a gatehouse and two round turrets which probably rose higher than they do today. It was also fronted by a barbican spanning a dry moat which would have incorporated a drawbridge and portcullis, but these were demolished in 1791.
Apart from being used as a defence structure it has also been used as a prison. The prison was built on the castle green enclosure in 1787 and enlarged by the Victorians in 1847. Imprisoned debtors were allowed some social contact but the regime for criminals was designed to be one of isolation. Consequently, the seating in the prison chapel is designed to enclose each prisoner individually so that the preacher could see everyone but prisoners could only see him. The castle ceased to be used as a prison in 1878. Many of the prisoners were deported to Australia and many more were executed on the ramparts on the tower at the north-east corner, overlooking the upper town. Prisoners were publicly hanged here for various crimes until 1868 and buried in the castle grounds where their graves can still be seen. These include the grave of William Frederick Horry the first person to be hanged by Victorian hangman William Marwood in 1872, and the first to die using the long drop method, which ensured that the neck was broken by the fall.
The grounds also contain remains of Lincoln's Eleanor cross. These are a series of 12 crosses erected by King Edward I (1274 – 1307) marking the nightly resting-places along the route taken when the body of his wife, Eleanor of Castile, who died in Harby near Lincoln, was taken to London.
At the western end of the castle facing visitors as they enter the Eastgate is an ivy clad building built in 1826 as the Assize courts these are still used today as Lincoln's Crown Courts. The south entrance porch was added in the early 20th century.
The most recent addition is the Heritage Skills Centre, which is the first new building within the Castle grounds for over 100 years. The Centre is a multi- functional building used for heritage crafts and skills development in Lincolnshire and provides short courses, lectures and demonstrations.
One of the main attractions is the Lincoln Magna Carta, the document is one of only four surviving originals sealed by King John after pressure from the rebellious barons at Runnymede in 1215. A ambiguous programme of renovation is currently (2013) underway to create a new exhibition centre to display Magna Carta; the construction of visitor facilities and opening sections of the prison within the castle to the public. It is planned be completed by April 2015, to coincide with the 800th anniversary of the signing of Magna Carta.
The Castle also holds historical re-enactments, jousting, brass bands, craft fairs and concerts and is one of the sites for the Lincoln Christmas Market which is held at the beginning of December each year.