[William Cloud Hicklin]

I had always assumed the reference was to the fall of Ithilien and East Osgiliath in Denethor I's time (although the EoA refernce to the Index I suspect has been garbled with DII's attempt belatedly to restore them).* Clearly the Rammas are some centuries old.

However, it's possible that they were even older, associated with the building of the beacon on Amon Din** and the fortification of Cair Andros, all the way back in the last days of the Kings, in which case the reference to Ithilien being under "shadow" would apply to the fall of Minas Ithil in 2000, or even the Wainrider/Harad alliance which nearly wrecked the kingdom in 1944.

Still, I think it is more likely that it was indeed the disaster of 2475 and the presence of the enemy in force just over the River, separated only by a bridge from MT's own townlands, which was the impetus for their fortification. It certainly can't be coincidence that the heaviest fortifications were devoted to the gate and causeway leading to Osgiliath- there was hardly a need so long as Osgiliath remained a fortress of Gondor.

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* For centuries it was thought that the wall built across northern Britain under Hadrian was the work of Septimus- since his inscriptions are all over it from the time he reconstructed it in stone ca. 200. Gildas was actually correct about the two walls and the identity of the Emperor who built the second, stone one- once you realize he wasn't talking about the Antonine wall at all, which he probably never heard of. The original construction under Hadrian was largely an earthwork (a fact not known until modern archaeology).

**Din was much older than the rest of the beacon-chain, which of course arose after the cession of Calenardhon to the Rohirrim. Din was built originally to relay communications between the City and Cair Andros.