[1] The manor took its name from the Old English name for the settlement, Cyningesburh, meaning "the king's fortress", and formed a large estate comprising 28 townships, centred on a fortified burh at Conisbrough itself.

[8] Hamelin extensively rebuilt the castle around 1180 to 1190, including constructing the stone keep; given his parvenu status, he probably hoped to reinforce perceptions of his new elevated rank.

[12] Conisbrough was inherited by William's young son John de Warenne in 1239, but he was still a minor and the castle was initially managed by his mother, Maud.

[13] Under John, Conisbrough's constables carried out a range of what the historian Stephen Johnson terms "colourful if rather unlawful dealings"; one was ultimately charged with having conducted "devilish and innumerable oppressions".

[16] Richard of York then inherited the castle, and on his death in 1460 during the Wars of the Roses it passed to his son Edward, who seized the throne in 1461, bringing Conisbrough back into Crown ownership once again.

[17] By the 16th century Conisbrough Castle was in a poor state of repair, and a royal survey carried out in 1537 and 1538 showed that the gates, bridge and parts of the walls had collapsed in a spectacular land slippage, and that one floor of the keep had also fallen in.

[20] The castle was not involved in the events of the English Civil War in the 17th century, and escaped the slighting that affected many similar properties, probably because the collapse of the outer walls had already made it indefensible and of little military value.

[24] Although the writer John Wainwright was still able to praise the "picturesque view" around the castle in 1826, the antiquarian Ecroyd Smith commented with concern in 1887 on the changing character of the location, in particular the factories that were growing up around the new railway line and the "murky atmosphere" the industrial works created.

[26] Limited repairs were subsequently approved by the trustees of Lord Conyers, although Clark's colleague, A. Ellis, expressed concerns that railings to protect the visitors who routinely climbed to the top of the keep had not been funded.

[29] Two sets of archaeological excavations were carried out on the site between 1967 and 1969, exposing the foundations of the buildings in the inner bailey, and then from 1973 to 1977, examining options for future visitor facilities.

[30] By 1984, when the government agency English Heritage took over the management of the property, the condition of the visitor services was unsatisfactory and the industrial character of the surrounding area was discouraging tourists.

[29] In response, English Heritage and Doncaster Metropolitan Borough Council formed a three-way agreement in 1988 with the Ivanhoe Trust, a local charity designed to generate new employment in the region.

[29] Under this agreement the trust would manage the site, English Heritage would maintain the historic fabric of the castle, while the council would construct a new visitors' centre.

[31] A new, controversial visitor's centre was built in the style of a collection of jousting tents, while the floors and roof of the keep were reinstalled between 1993 and 1995 with European Union funding, in an attempt to limit the erosion of the castle stonework.

[39] The oval inner bailey was formed by scarping and counter-scarping the natural contours of the hill, producing a bank, now largely destroyed, and a protective ditch.

[40] The wall was defended by six mural towers along its southern and western sides, of which three still survive reasonably intact, and strengthened with pilaster buttresses along the northern edge.

[45] Along the north side was the hall, pushed into an awkward corner of the curtain wall, 70 by 30 feet (21.3 by 9.1 m) in size and originally probably built two storeys high.

[49] The keep comprises a central circular tower, 62 feet (19 m) in diameter, with six, large solid buttresses projecting outwards to form an hexagonal design, unique in England.

[50] The current concrete stairs to the keep are modern, and the original medieval stairway, made from timber and stone, would have incorporated a drawbridge just before the castle doors.

The central circular tower provided defensive advantages but the buttresses introduced 12 vulnerable corners into the stonework, and the keep itself had no arrow slots to permit the defenders to fire on any attackers.