Hi Miguel,
I dont recall offhand where I've seen these type charts for development of various sword categories and forms, but I have of course seen them...it seems in a Polish book and some others. There have been some pretty good discussions on the development of sabres, one that got pretty involved in 2004-2005, I'll have to look for the thread title.
Excellent information Fearn!! and it must be exciting to get to your books! The last time I saw the majority of mine was in the blur of the movers taking them to storage nearly two years ago when I left on this odyssey!
I got just the key references stashed in the bookmobile (my wife was finding books hidden in every nook and crannie in the RV over weeks).
I do recall some years ago researching Central Asian swords, and as David Nicolle has noted (in the Osprey reference shown here) , "...there is no evidence that the Huns used single edged sabres". The swords they used were of long Sassanian type. The 7th to 8th century estimate for the increased presence of the curved sabre seems generally agreed upon, and this seems to have evolved in the western frontiers of China, most likely in Turkestan. It is believed however, that the curved blade was known in China as early as the 5th century. In any case, there was never a complete supplanting of the straight bladed swords, and both types found use concurrently in varying degree.
I think it is important to consider as well that the description 'Hun' became a rather collectively applied term for nomadic tribes of the steppes, and the hordes assembled and unified in confederation by Attila, comprised many tribal groups. It is still debated whether the Hsiung Nu of Mongolian regions from 3rd century BC and moved westward early in the new millenium are actually the core of these Hun tribes, though it does seem most likely.
In "50 Military Leaders Who Changed the World" (Wlliam Weir, 2007, p.56) it is noted that "...for close fighting, the Huns used a lasso and a long, straight, single edged sword called a 'urepos'".
There was a great article written by Helmut Nickel in 1973 in the Metropolitan Museum Journal (7), titled "About the Sword of the Huns and the Urepos of the Steppes", which I unfortunately do not have with me. Perhaps this might have some information to add.
I do recall that there was some discussion concerning sword worship practiced by the Huns that may have involved the shortsword/dagger of Scythia and Persia known as the 'akinakes' in "The World of the Huns" (Otto Maenchen-Helfen, 1973), also not with me.
I think the idea that the Huns carried curved sabres must have arisen from the term 'gladius hunnicus' (Nicolle, op.cit.) applied to the sabre in Central Europe later, and describing swords used by steppes horsemen. The 'Hun' term was probably used much in the sense that 'Mongol' was applied broadly to nomadic horsemen in the medieval period, by this time with the curved sabre clearly in use.
All best regards,
Jim