toxic-nova said:
I'm not sure how well developed the Viking trading empire was. I know Vikings, or Varangian Guards, were special soldiers even in the Byzantine Empire. So from pure facts Viking could have knowledge of old Roman warfare and knowledge about their wars. But, I don't think that Viking trading worked this way.
And which Nordic god represents the archer?
Well, the Vikigns probably had contact with the Magyars in Hungary, which were extremely adept at riding and hrose archery. But it wasn'T something that a Viking Warband would train - no place for horses for every warrior on a longship. As I said there are finds that hint at composite bows in Birka, to be exact wall mounts of a type that were used by said Magyars for their side quivers, which were rather large and included a small 'roof' to keep the arrows dry. But it is probably that in this case those bwos were used by Magyar mercenaries paid for by the Birka garrison since the Svear (and other Nordic peoples) didn't rely on Bows as a weapon but rather as a tool for hunting.
If you're interested have a look at this short archeological paper: http://www.academia.edu/1429936/Eastern_archery_in_Birka_s_Garrison
That article also mentions a possible composite bow shortly glimpsed in Beowulf.
For the possible evidence of one composite bow used in iceland, have a look at this neat homepage: http://www.hurstwic.org/history/articles/manufacturing/text/viking_bow.htm
And the gods for archery were Ullr and Skadi; both gods of archery AND hunting. In Ullrs Case also Skiing.