When did JRRT decide to give Boromir a shield?

[Flammifer]

In TLOTR Boromir's shield is mentioned only twice (I think). Once when the equipment of the Company is detailed as they leave Rivendell; again in Aragorn's second verse (the third verse of the poem) sung when Boromir's funeral boat is launched into the Anduin. The shield is not mentioned on Caradhras (when it should have been useful as a snow plough, snow shovel, and sled), at Boromir's battle with the Orcs at Parth Galen (when is should have been useful against the arrows), in the text when Boromir's body and equipment are loaded into the boat (when all the rest of the equipment loaded is enumerated).

Could it be that JRRT first conceived of Boromir's shield when he composed Aragorn's song, and then revised his description of Boromir's equipment during the leaving of Rivendell to include the shield (but didn't revise other passages where a shield might have been included)? Or, did JRRT include Boromir's shield in the first draft of leaving Rivendell, and then forget about or ignored it until he composed the poem?

Perhaps someone who has better access to 'The History of Middle Earth' could shed some light on this?

 

[Makar]

My guess: he did not take it with him when running after Merry and Pippin (and he had no use for it when going after Frodo). The usefulness with snow is hotly ( hah!) debated elsewhere on this fine forum.

 

[Flammifer]

My guess: he did not take it with him when running after Merry and Pippin (and he had no use for it when going after Frodo). The usefulness with snow is hotly ( hah!) debated elsewhere on this fine forum.

Hi Makar,

I am more interested in which came first, the reference to the shield in the poem, or that when leaving Rivendell (in the course of JRRT's drafts I mean)? Can this be discovered in 'The History of Middle Earth'?