"elder" and "younger" families of gods, as with the Titans versus the Olympians of ancient Greece, the Æsir and Vanir were portrayed as contemporaries. The two clans of gods fought battles, concluded treaties, and exchanged hostages (Freyr and Freyja are mentioned as hostages). An áss like Ullr is almost unknown in the myths, but his name is seen in a lot of geographical names, especially in Sweden, and may also appear on the 3rd century Thorsberg chape, suggesting that his cult was widespread in prehistoric times. The names of the first three Æsir in Norse mythology, Vili, Vé and Odin all refer to spiritual or mental state, vili to conscious will or desire, vé to the sacred or numinous and óðr to the manic or ecstatic. Æsir and Vanir A second clan of gods, the Vanir, is also mentioned in Norse mythology: the god Njörðr and his children, Freyr and Freyja, are the most prominent Vanir gods who join the Æsir as hostages after a war between Æsir and Vanir. The Vanir appear to have mainly been connected with cultivation and fertility and the Æsir were connected with power and war. In the Eddas, however, the word Æsir is used for gods in general, while Asynjur is used for the goddesses in general. For example, in the poem Skírnismál, Freyr was called "Prince of the Æsir". In the Prose Edda, Njörðr was introduced as "the third among the Æsir", and among the Asynjur, Freya is always listed second only to Frigg. In surviving tales, the origins of many of the Æsir are unexplained. Originally, there are just three: Odin and his brothers Vili and Vé. Odin's sons by giantesses are naturally counted as Æsir. Heimdallr and Ullr's connection with the Æsir is not clearly mentioned. Loki is a jötunn, and Njörðr is a Vanir hostage, but they are often ranked among the Æsir. Scholarly theories and interpretations Given the difference between their roles and emphases, some scholars have speculated that the interactions between the Æsir and the Vanir reflect the types of interaction that were occurring between social classes (or clans) within Norse society at the time. According to another theory, the Vanir (and the fertility cult associated with them) may be more archaic than that of the more warlike Æsir, such that the mythical war may mirror a half-remembered religious conflict. This argument was first suggested by Wilhelm Mannhardt