Thank you Michael, it is very interesting, but also complicated.
A friend sent me the following link
http://www.bhagavadgitausa.com/TILAKAM.htm which is huge, and so far I have not read it all, but it gives some interesting explanations. One of the problems is, that some of the symbols may have meant something if you believed in one religion, and something else if you believed in another religion, but many of the symbols on the blades were only used by one religion. But if captured, a good blade was still a good blade, and was used by the capturer.
Jens