Following the successful Norman invasion of England in 1066 (and I could have advised Harold Godwinsson how to repel it - after the forced march from his victory at Stamford, he should have razed the crops and undertaken a 'scorched earth' and limited warfare policy, until the rising Equinoctal gales in the Channel had cut William the Bastard off from any resupply; obviously, he wasn't a disciple of Sun Tzu, and OS hadn't been born yet) the Norman forces - and their many mercenary allies - sought to subdue the countryside as soon as possible.
This they did by throwing up a series of 'motte and bailey' fortifications. This involved digging a ditch, using the spoil to raise a rampart and topping it with a wooden wall, or palisade, then erecting a simple earthen mound (the 'motte') inside the enclosure (or 'bailey'). This was topped by a strongpoint or building, usually also of wood, but replaced by stone as soon as possible. The traces of many of these sites can found in many parts of the country; in Derbyshire they can be found at Duffield, Melbourne and Morley Motte.
However, the feudal society that the Normans were imposing on an unwilling people, demanded strong, well-defended bases from which the new overlords could ride out and subdue the countryside. That meant strong stone keeps, initially, followed by ever-more complex outer walls, studded with watchtowers and fortified strongpoints. William the Conqueror had caused a magnificent square fortress, the Tower of London to be erected (incorporating part of the old Roman city walls), but further north, noblemen who had been granted manors and the lands previously held by Saxon nobles, sought to chose sites which took advantage of topographical features to enhance their new castles.
William Peverel (1040 - 1115) was an especial favourite of the Conqueror - yes, the spelling was different to the modern one, but names were rather mutable, back then, just look at the alternate spellings used for William
Shakespear Shakspeare Shakespear Shakspeare Shakspere, oh blast, Shakespeare! It is said by some that Peverel was a natural son of William the Conqueror, by others that he had been William's standard bearer. Whatever the truth, he was given enormous grants of land in Nottinghamshire and Derbyshire - no less than 162 manors, according to that immense tax census of 1086, the 'Domesday Book'. He began construction of Peveril Castle around 1080, and the site was probably one of the most imposing in England. The hill rising up from the Hope Valley is extremely steep, making a frontal assault by an enemy on foot extremely difficult - an assault by mounted knights would have been almost impossible. The use of siege engines - such as a bombardment by trebuckets - would have been out of the question; it would not have mattered if they were hurling ripe pumpkins rather than stones, their missiles would not have reached!
So, if archers on the newly-constructed curtain wall could have kept opposing forces at bay, what about an approach from the rear? There Peveril Castle is even better protected, with a vertical cliff face many hundreds of feet high, rising from the floor of Cave Dale. Access to the castle was via a wooden bridge spanning the steep gorge to the north.
When the Normans took England, as well as establishing the feudal system they took huge swathes of forest land under control, to create royal hunting preserves - Norman noblemen loved hunting above all things, it seems. The Royal Forest of the Peak was controlled from Peveril Castle, and this gave the castle its importance. Unfortunately, William Peveril the Younger fell foul of King Henry II in 1155, and his lands and the castle were confiscated. Henry II visited the castle a few times, the first time, in 1157, he played host to King Malcolm IV of Scotland. The young King of the Scots did not do well at this meeting, being forced to give up the former English lands of Northumberland and Cumbria, and being given the Earldom of Huntingdon (which had been his father's) in return.
Eventually, the castle fell into the hands of John of Gaunt, Duke of Lancaster, who did not care much for his new possession. Peveril Castle fell slowly into disrepair, and was abandoned. The Crown still holds it through the Duchy of Lancaster, however (the Sovereign, in modern times, is also the Duke of Lancaster). It is now preserved by English Heritage, and classified as a Grade 1 Listed Building and a scheduled monument.
Peveril Castle has had an eventful life, but still gives huge pleasure to thousands of visitors, each year!