The recorded history of Luxembourg begins with the acquisition of ''Lucilinburhuc'' (today Luxembourg Castle) situated on the Bock rock by Siegfried, Count of the Ardennes, in 963 through an exchange act with St. Maximin's Abbey, Trier. Around this fort, a town gradually developed, which became the center of a state of great strategic value within the Duchy of Lorraine. Over the years, the fortress was extended by Siegfried's descendants and by 1083, one of them, Conrad I, was the first to call himself a "Count of Luxembourg", and with it effectively creating the independent County of Luxembourg (which was still a state within the Holy Roman Empire).