One day in mid-October 1355, a Scottish raiding party, laden with booty, crossed the River Tweed back into Scotland at the ford at Norham in North-umberland. The constable of Norham castle, Sir Thomas Gray, quickly mustered his garrison and set off in hot pursuit of the raiders. Unfortunately, it was a trap, and a few miles into Scotland Gray and his men were ambushed by a much stronger Scottish force. After a fierce struggle, Gray was captured, and hauled off to imprisonment in Edinburgh castle. To while away the long hours of his captivity, he decided to write a book of ‘the chronicles of Great Britain, and the deeds of the English’. The result of his endeavours was the Scalacronica; and given that we owe its very existence to war, it is not perhaps altogether surprising that the subject of war has a prominent place in the work.

As the circumstances which led to the writing of the Scalacronica suggest, Gray was an active knight who spent his adult life in military service. This was mainly against the Scots, though he served on Edward III's somewhat lacklustre campaign in Flanders in 1338–9, and on his rather more impressive French campaign of 1359–60. These, and other campaigns, are described in some considerable detail in Gray's work. Unfortunately, however, the sole surviving manuscript of the Scalacronica lacks a quire covering the period 1340 to 1355.