As well as I know it was done from same steel and with managing carbon content on the surface of the steel burning it out or enriching it and then folding and folding they create excellent blades - like Top grade katanas from Japam. So it is made from same steel folded many times. In Japan it was made from tamahagane.
Now I think I know what you're talking about. It is true that Japanese technique involves folding with roughly homogenous material. As I'm sure you know, there are several variations to this too, but it's not my area of interest. Of course I don't think I've heard anyone call Japanese swords 'damascus' either.
The pattern welding people are talking about most often--laminates of differing layers of material being twisted, coined, etc. is extremely ancient. I mentioned earlier the swords found at LaTene dating from 500 to 300 BC, as an example.
A good example of this is the Celtic/heroic/migration/Viking weapons (though the technique was used just about everywhere in one form or another).
There is speculation as to why a smith would use differing grades of material from very high-carbon steel all the way to WI in a weapon. It is thought that they sought to benefit from the impact-resistance of the softer grades mated to the edge-holding of the higher grades (rough high-carbon steel) which might prove too brittle if used solely to make a long weapon.
This, I think, is bolstered by the arrangement of the steels in a typical Viking sword (harder edge welded to a somewhat softer core which is made up of multiple bars of steel twisted with other steel or iron.)
Going back further, Caesar notes in his commentary on the Gaelic wars, that his opponents used very long swords which required frequent straightening during battle. This is the type of behavior one would expect from a long sword made in this fashion.--perhaps hard on the edge, but more likely to bend than break--perhaps a tad too likely to bend if you follow Caesar's implication.
There is the added curiosity that many fine pattern welded swords have been found in burial mounds, etc. that, upon analysis, have proven not to be hardened at all. Some speculate that the sword might have been ritually 'killed' by annealing, but there is a troubling lack of evidence --essentially none that I know of---for that theory.
Regardless, these ancient techniques of weapon making (combining different grades of steel sometimes with iron for whatever reasons) are very similar to what modern makers do today. I, for one, don't use anything but all high-carbon materials in any pattern welded mix for performance and constancy sake, though some folks do. 1095 and 203-E is a good example of a High-carbon mated to a non-heardening material. 203-E is essentially mild steel with nickel.
