Analysis of information sources in references of the Wikipedia article "丹麦国旗" in Chinese language version.
Legend states that a red cloth with the white cross simply fell from the sky in the middle of the 13th-century Battle of Valdemar, after which the Danes were victorious. As a badge of divine right, Denmark flew its cross in the other Scandinavian countries it ruled and as each nation gained independence, they incorporated the Christian symbol.Inge Adriansen, Nationale symboler, Museum Tusculanum Press, 2003, p. 129: "Fra begyndelsen af 1400-tallet kan Dannebrog med sikkerhed dokumenteres som rigsflag, det vil sige statsmagtens og kongens flag" (English: "Dannebrog can with certainty be documented as flag of the realm, that is the flag of the authority of state and of the king, from the beginning of the 1400s")
许多以基督教为主的国家的国旗上都印有十字架，象征着基督教。北欧国家——丹麦、芬兰、冰岛、挪威和瑞典——国旗上的斯堪的纳维亚十字或北欧十字也代表基督教。。细长的十字图案随后被其他北欧国家采用：瑞典、挪威、芬兰、冰岛和法罗群岛，以及不列颠群岛设得兰群岛和奥克尼群岛。
