Question: What nickname was sometimes applied to the King who signed a treaty with the men of Kent at the site of Stone Castle ?

Context paragraphs:
Deal Castle: Deal Castle is an artillery fort constructed by Henry VIII in Deal, Kent, between 1539 and 1540.  It formed part of the King's Device programme to protect against invasion from France and the Holy Roman Empire, and defended the strategically important Downs anchorage off the English coast.  Comprising a keep with six inner and outer bastions, the moated stone castle covered 0.85 acre and had sixty-six firing positions for artillery.  It cost the Crown a total of £27,092 to build the three castles of Deal, Sandown, and Walmer, which lay adjacent to one another along the coast and were connected by earthwork defences.  The original invasion threat passed but, during the Second English Civil War of 1648–49, Deal was seized by pro-Royalist insurgents and was only retaken by Parliamentary forces after several months' fighting.

Stone Castle: Stone Castle is a castle at Stone, near Bluewater in Kent, England.  It was built between 1135 and 1140 on the site where William the Conqueror signed a treaty with the men of Kent in 1067.

Kabi Lungchok: Kabi Lungchok is a historic site of significance, which is located 17 km north of Gangtok on the Northern Highway in northeastern Indian state of Sikkim.  The historicity of the site is attributed to the fact that the Lepchas, the ethnic tribals of Sikkim and Bhutias (ethnic Bhot), the immigrants from southern Bhot who settled down in Sikkim from the 14th century onwards, ceremonially signed a "Treaty of Blood Brotherhood" with religious fervour.  Stone pillars mark the location where the treaty was signed.  The Treaty was signed at Kabi Lungchok by the Bhot King, Khye Bumsa representing the Bhutias and the Lepcha Chief Thekong Tek.  The literal meaning of 'Kabi Lungchok', pronounced ‘Kayu sha bhi Lungchok’, is "stone erected by our blood."  Life-size statues of the Lepcha and Bhutia 'blood-brothers' who signed the treaty has been erected here.

Kistvaen: A kistvaen or cistvaen is a tomb or burial chamber formed from flat stone slabs in a box-like shape.  If set completely underground, it may be covered by a "tumulus".  The word is derived from the Welsh "cist" (chest) and "maen" (stone).  The term originated in relation to Celtic structures, typically pre-Christian, but in antiquarian scholarship of the 19th and early 20th centuries it was sometimes applied to similar structures outside the Celtic world.

Bedrock mortar: A bedrock mortar (BRM) is an anthropogenic circular depression in a rock outcrop or naturally occurring slab, used by people in the past for grinding of grain, acorns or other food products.  There are often a cluster of a considerable number of such holes in proximity indicating that people gathered in groups to conduct food grinding in prehistoric cultures.  Correspondingly the alternative name gossip stone is sometimes applied, indicating the social context of the food grinding activity.  Typical dimensions of the circular indentations are approximately 12 centimeters in diameter by 10 centimeters deep, although a considerable range of depths of the cavities have been documented .  The bedrock mortar has been identified in a number of world regions, but has been particularly intensely documented in the Americas.  An alternative term for the bedrock mortar site is bedrock milling station.

Glen Eyrie: Glen Eyrie is an English Tudor-style castle built in 1871 by General William Jackson Palmer, the founder of Colorado Springs.  There are 17 guest rooms (12 Deluxe guest rooms and 5 premier guest rooms) in the castle, as well as 7 meeting rooms to include the Castle Great Hall (2200 square feet room in the castle that can hold up to 240 people) and 2 dining rooms in the castle (The Castle King James Hall has seating for 180 people and the Castle Music & Library rooms for seating for up to 58 people).  This house was his and his wife's dream home and is near Colorado Springs in the northwest foothills just north of the Garden of the Gods rock formations (now a city park).  After building a large carriage house, where the family lived for a time, Palmer and his wife Mary (Queen) Mellen built a 22-room frame house on the 800 acre estate.  This house was remodeled in 1881 to include a tower and additional rooms, and made to resemble a stone castle in 1903, reminiscent of those native to England.

Cilgerran Castle: Cilgerran Castle (Welsh: "Castell Cilgerran" ) is a 13th-century ruined castle located in Cilgerran, Pembrokeshire, Wales, near Cardigan.  The first castle on the site was thought to be built by Gerald of Windsor around 1110–1115, and it changed hands several times over the following century between English and Welsh forces.  In the hands of William Marshal, 2nd Earl of Pembroke, the construction of the stone castle began after 1223.  After passing through successive families, it was left to ruin and eventually abandoned by 1400.  The castle backs onto a cliff face, with the remaining ruins dating from the 13th century.  It was most heavily fortified where it faces inland, and includes a pair of drum towers rather than a central keep which remain.  It passed into the hands of the National Trust in 1938, who open it to the public.

Stone cladding: Stone cladding is a thin layer of real or simulated stone applied to a building or other structure made of a material other than stone.  Stone cladding is sometimes applied to concrete and steel buildings as part of their original architectural design.

Walmer Castle: Walmer Castle is an artillery fort originally constructed by Henry VIII in Walmer, Kent, between 1539 and 1540.  It formed part of the King's Device programme to protect against invasion from France and the Holy Roman Empire, and defended the strategically important Downs anchorage off the English coast.  Comprising a keep and four circular bastions, the moated stone castle covered 0.61 acre and had 39 firing positions on the upper levels for artillery.  It cost the Crown a total of £27,092 to build the three castles of Walmer, Sandown, and Deal, which lay adjacent to one another along the coast and were connected by earthwork defences.  The original invasion threat passed, but during the Second English Civil War of 1648–49, Walmer was seized by pro-Royalist insurgents and was only retaken by Parliamentary forces after several months' fighting.

William the Conqueror: William I (c. 1028 – 9 September 1087), usually known as William the Conqueror and sometimes William the Bastard, was the first Norman King of England, reigning from 1066 until his death in 1087.  A descendant of Rollo, he was Duke of Normandy (as Duke William II) from 1035 onward.  After a long struggle to establish his power, by 1060 his hold on Normandy was secure, and he launched the Norman conquest of England six years later.  The rest of his life was marked by struggles to consolidate his hold over England and his continental lands and by difficulties with his eldest son.

Supporting paragraphs: Stone Castle William the Conqueror
Answer: William the Bastard