Why Didn't The Targaryens Do More To Help The Night's Watch

We know now that House Targaryen has known about the song of ice and fire prophecy and the threat of the others north of the wall since the days of Aegon the Conqueror, so why does it seem like they did so little to help the nights watch and prepare them for the threat? Today I will explain what I think is the most reasonable answer. Check out my twitch here https://www.twitch.tv/michaeltalksaboutstuff Check out this video by glidus where he learns what the actual translation of the High Valyrian song, the song of ice and fire from the mad king stage play is https://www.youtube.com/watch?v=r4MpubKBsUY Check out some of my other videos too and also have a nice day while you are at it.