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Siege of Rochester Castle


Introduction to Rochester Castle

Rochester Castle was originally constructed by Gundulf, Bishop of Rochester, in the 1080s. It is one of the earliest Norman stone keeps to be built in England following the Norman Conquest of 1066.

In 1127, Henry I instructed Archbishop of Canterbury, William de Corbeil, to build a great stone keep. Standing at 113ft, it is the tallest medieval stone keep in England.

The castle endured three sieges, including the famous siege by King John in 1215, when the south-eastern tower of the castle came crashing down.

Failure of Magna Carta

1215 is remembered primarily for Magna Carta, the famous royal charter signed at Runnymede, where rebellious barons aimed to restrict the power of King John in an iconic moment for democracy.

Whilst Magna Carta represented an important challenge to royal power, it was not successfully enforced. Pope Innocent III issued a papal bull declaring it null and void, and neither King John, nor the barons kept to the terms of the charter.

Hostilities between the barons and King John remained high and, just months later, a group of rebellious barons decided to take matters into their own hands, leading to the First Barons’ War (1215 – 1217).

Barons seize Rochester Castle

King John was in south-east England recruiting mercenaries to take on the barons. Rochester Castle was strategically significant as it commanded an important river crossing on the River Medway on John’s route to London.

The barons, led by William d’Aubigny, seized Rochester Castle with around 100 knights. John immediately rode to Rochester, arriving on 13 October.

Inside pillars of Rochester Castle in Kent.
The interior of Rochester Castle today, with the central wall clearly visible.

John lays siege to the castle

Between October and December, King John laid siege to Rochester Castle to retake it from barons. After successfully taking Rochester Bridge and captured the castle bailey, the royal army used five siege engines to bombard the rebels inside the keep with stones.

The siege engines were failing to breakthrough through the thick walls of the stone keep, so John decided to change approach, instructing his miners to tunnel beneath the south-east tower.

John then issued one of the strangest royal commands, requesting the fat of ‘40 pigs too fat to eat’ to ignite the timber props they had used to support the mine beneath the keep.

The mine was lit, and the fire brought down the south-east corner of the keep, however it was starvation that finally forced the rebels to surrender.

Rochester Castle and the fall of the south-east tower by King John's siege in 1215
Visualisation of the collapse of the south-eastern tower.


King John’s victory was short-lived as he died of dysentery in 1216. John was succeeded by his nine year-old son, Henry III, who was able to ward off the threat of Prince Louis of France with support from his barons.

Under Henry III, the fallen tower of Rochester Castle was rebuilt with the round design we can still see today.

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