Castle and cathedral have faced each other across the hilltop since Norman times. Lincoln Castle was raised over the southwest quarter of the citadel by order of William the Conqueror in 1068. The site had previously been densely occupied – Domesday Book tells us that 166 houses were destroyed to make way for the castle. Its stonewall is mentioned as early as 1115 and Henry I is regarded as the likely builder.
The high curtain, still intact though frequently patched up in later centuries, preserves portions of herringbone masonry confirming its early Norman date. It stands on top of an earth rampart surrounding a large, roughly square bailey. A rare feature is the presence of not one but two mottes, both on the southern edge of the bailey. Why they should stand so close together is a mystery, since they seem to threaten each other from a defensive point of view. The larger motte is crowned by a polygonal shell keep known as the Lucy Tower, evidently a later Norman addition and possibly erected by the Earl of Chester, who held Lincoln for the Empress Matilda.
The smaller motte carries the so-called Observatory Tower, an early Norman structure extended in the fourteenth century and capped by a Victorian turret. Cobb Hall, a horseshoe-plan tower flanking the vulnerable northeast corner of the walled circuit, is a defensive improvement made after an unsuccessful siege by the Dauphin Louis’ supporters in 1217.
There are two gatehouses. The West gate, now blocked, is a simple Norman gate tower. The East Gate was re-fronted in the fourteenth century with a lofty gate arch and round turrets corbelled out higher up. Foundations of a barbican can be seen in front, but the courtyard extension of the gatehouse is another Victorian embellishment. It incorporates an oriel window from a medieval house in the city.