in 1192, Queen Eleanor addressed a letter to the monks of the Holy Trinity at Canterbury begging them to assist in repairing the walls of that city, and promising that their so doing should not be considered a precedent (Balland and Tait)
When Richard was in captivity abroad, it appears that the neighbourhood of Canterbury being in a state of disturbance, it had become necessary to protect the city with walls, ditches, and other defences:—as may be seen in a charter of Queen Eleanor, granted, in her son's absence, to the prior and convent of Canterbury, and which stated,—that the men of the prior and convent had worked at the walls, not as of right or by custom, but at the instance of the queen; such work done of necessity, and from the intervention of the queen, should not affect the liberties, the prior and convent enjoyed under various grants;—a strong instance of the caution which the ecclesiastics then exercised to protect their privileges: and also a proof of their general exemption from these burdens. (Merewether and Stephens)