Asatru is not a new age religion. In fact it is very old. It can be traced back to around 1000 BCE (Before common era) when the ancestors of the Germanic people, settled in the general area of Scandinavia and began to develop a language, culture, and religion separate from the rest of the Indo-European stock. Considering the Indo-European migrations started around 4000 BCE it is safe to say that our religion developed somewhere along the way. Way before Christianity was ever thought of. It is said that Odin found the runes in 250 BCE and revealed them to humankind. Tacitus confirms this in his writings THE GERMANIA in 98 CE which is the earliest full account of the culture and religion of the Germanic people. Incidents that took place around this time and over the next 1000 years were vital to Asatru's survival. In 9 CE Hermann defeated Roman forces at the battle of Teutoburger Wald preventing the Roman conquest of Germania that would surely have stamped out our religion in that area. But the fight was far from over. A new enemy was plotting a much worse attack on Asatru and other pagan religions. Christians planned to convert the world.
http://winterscapes.com/einherjar/asatru.htm
http://winterscapes.com/einherjar/asatru.htm