Helm’s Dike

We have no record of the making of the Dike. It may in principle have dated back to the last years of the Second Age, during which the early Gondorians constructed the castle at Aglarond that would later be called the Hornburg. As an earthwork rampart rather than a work of stone, its nature perhaps fits more readily with the culture of the Rohirrim than the ancient Gondorians, in which case it would have been raised no earlier than the founding of Rohan in III 2510. It may have been of later construction than even this, raised by Helm Hammerhand himself to defend the Deep where his people were taking shelter, which would probably date it to III 2758. Our earliest definite record of the Dike was in the following year, III 2759, when Helm's frozen body was discovered standing on the earthen rampart.

Though the Dike was known as 'Helm's Dike', it's far from clear how it acquired this name. One obvious explanation would be that Helm himself ordered its building (and indeed the name recalls the famous Offa's Dyke that runs along the border between Wales and England, generally presumed to be named for Offa, the King of Mercia who had it made). This is plausible, but given our relatively detailed accounts of Helm's history it seems strange that his building of the Dike is never mentioned.

Alternatively, the Dike may have predated the time of King Helm, but been given his name after he sheltered his people in the Deeping-coomb at the time of Wulf's brief occupation of Rohan. This was true of the Deep itself, which gained the name 'Helm's Deep' from these events. The fact that Helm's body was found on the Dike would reinforce this connection, helping the old earthwork to gain a new name, 'Helm's Dike', though it might conceivably have been standing for centuries, or even millennia, before Helm's time.