The position of Nottingham was one of great military importance; for lying almost at the centre of the kingdom, the town held the approach to the one bridge over the Trent by which the main road from the south struck northward: and further commanded the navigation of the river from the point where, broadened by the confluence of the Derwent and the Soar, it became a great highway of internal communication. Throughout its history, therefore, from the time of the Danes down to the time of the Civil War, Nottingham could not be left out of account when any fighting was going on. But England was in the main a land of peace, and the occasional and intermittent importance of an internal fortress was wholly different from the consequence that attached to a border castle like that of Bristol, or to outposts against foreign foes such as the walled seaport towns of the coast. Hence the military advantages of its site made but little mark on the character and history of the town, and the castle which crowned the sandstone cliff that rose precipitously from the waters of the river Lene played no great part in the life of the mediæval borough. Lying well out of reach of all foreign foes, it fell into no misfortunes such as Rye, which was destroyed by fire twice in half a century, nor was it impoverished by taxes for defence against the French such as threatened to leave Southampton desolate; and its merchants were only occasionally required to make contribution towards the protection of the coast and the safety of the sea-borne trade which added to their wealth and luxury. Thus, when the keeping of the sea was given in 1406 to the English merchants, their elected Admiral of the Fleet, Nicholas Blackburn, wrote a peremptory order to Nottingham for £200 as its share of the cost;[621] but the merchants’ experiment failed, and they were relieved of their responsibility before they had levied any second toll.