Christians who demonized everything that wasn't them, up to an including putting horns of Vikings even though that simply never happened. But, gotta make those heathens look more like the devil,
Somewhat similar to the way medieval Christians are demonised now as the cause of all evil via simplistic and misleading historical myths.
It wasn't Christians who invented this to make them "look like the devil", it was a product of 19th C artistic license and the Romantic tradition. The main source of its popularisation was costumes in Wagner's
Ring cycle.
Medieval Christians did not depict them with horned helms.
My pagan and heathen ancestors, for example, had female priests and warriors. Christianity is still struggling with the idea of women not having to be inherently submissive to men.
The idea that women were significantly more emancipated in pre-Christian society is somewhat misleading. In the move to Christianity women probably lost out in some areas and gained in others. In neither were they in a particularly emancipated state though.
Women could play an important role in political and military affairs in the Christian world:
Iron Ladies of the Ancient World - Mavia of Arabia - Archaeology Magazine Archive
Aethelflaed, Lady of the Mercians
Eleanor of Aquitaine - Wikipedia
Abbesses could play significant roles in religious and social affairs, for example:
Hildegard of Bingen - Wikipedia
Hilda of Whitby - Wikipedia
As with Pagan society, women also could conduct business, own property, etc.
There were some positive developments too. For example, generally, in European Pagan society, unmarried and married women were literally the property of men and had no consent over their own bodies (although could perhaps gains osme autonomy as widows). So the idea that women were 'subservient to men' was hardly a Christian regression from a more enlightened Paganism.
If salient features of the pagan legacy persisted throughout the millennium of the Germanic-nordic continuum, it is nonetheless true that Christianity introduced radical changes into women's lives. The new religion's most original contribution to the feminine condition was the insertion of gender equality into marriage and sexual relations. This program would obviously benefit most the gender that had suffered discrimination.
Churchmen were unable and indeed did not wish -to interfere in all areas where women were treated unequally, but in matrimonial matters they sought to establish gender symmetry. Most successful was their program concerning consent. In Roman law the father had exercised decisive authority over the marriages of both his sons and daughters; according to Germanic custom the men themselves chose their wives. Familiar with both systems, churchmen preferred the Germanic approach but sought to extend the marital choice to women as well.
Consent in marriage meant little to Germanic and nordic men who already enjoyed this privilege, but, if and when implemented, it was an extraordinary change for women. The silent pagan bride, transferred like property from father to husband, was replaced by the articulate Christian woman who · by her own "yes-word" (jayroi) was allowed to affirm her willingness to share her life with a man who already had consulted her, not just her father.
Fathers of daughters may have appreciated this new female freedom, but it was not necessarily received with favor by the groom or his kinsmen, who were more preoccupied with the economic and political advantages offered by the bride and her family than with personal relations. One may further speculate that affective marriages -that is, marriages containing mutual marital affection -were encouraged when a woman had given her consent.
The doctrine of consent was introduced to the north through ecclesiastical correspondence between Norwegian and Icelandic prelates beginning in the late twelfth century, in which the Archbishop of Nioar6ss (Trondheim) brought the new legislation to the attention of his suffragans...
Gender equality is also evident in the stipulation that men and women were to be punished equally for sexual crimes other than illegitimacy. Gragas had defined unlawful intercourse (legoro) as the crime committed by a man when he slept with a woman over whom he had no sexual rights. In contrast, Bishop A.rni's law distinguished fornication (einfaldr h6rd6mr; literally, single adultery) from adultery (tvifaldr hordomr; literally, double adultery), and applied them to both men and women according to their marital status (NgL 5:39). Without using the term, the so-called Older Christian Borgarthing Law had already conceived of single adultery and had ordered both a married man and a married woman to pay a fine of three marks if they slept with an unmarried partner (NgL 1:351).
The principle of gender equality may derive from churchmen's underlying concern for humans as individuals. In the pagan culture only the man was accounted an individual who took responsibility not merely for his own actions but also for those of his wife and daughters. When a pagan woman committed a crime, her husband had to answer in court, as Gunnarr did for Hallgerdr after she ordered her slave to steal food. A pagan woman was not considered capable of committing sexual crimes but was regarded as damaged property.
Women in Old Norse society - Jenny Jochens