The pagan religion of the Germanic tribal confederation of the Franks has been traced from its roots in polytheistic Germanic paganism through to the incorporation of Greco-Roman components in the Early Middle Ages. This religion flourished among the Franks until the conversion of the Merovingian king Clovis I to Nicene Christianity (c. 500), though there were many Frankish Christians before that. After Clovis I, Frankish paganism was gradually replaced by the process of Christianisation, but there were still pagans in the late 7th century. The majority of pagan Frankish beliefs may share similarities with that of other Germanic peoples. If so, then it may be possible to reconstruct the basic elements of Frankish traditional religion. The migration era religion of the Franks likely shared many of its characteristics with the other varieties of Germanic paganism, such as placing altars in forest glens, on hilltops, or beside lakes and rivers, and consecration of woods. Generally, Germanic gods were associated with local cult centres and their sacred character and power were associated with specific regions, outside of which they were neither worshipped nor feared. Other deities were known and feared and shared by cultures and tribes, although in different names and variations. Of the latter, the Franks may have had one omnipotent god Allfadir ("All Father"), thought to have lived in a sacred grove. Germanic peoples may have gathered where they believed him to live, and sacrificed a human life to him. Variants of the phrase All Father (like Allfadir) usually refer to Wuodan (Woden, Óðinn/Odin), and the Franks probably believed in Wuodan as "chief" of blessings, whom the first historian Tacitus called "Mercurius", and his consort Freia, as well as Donar (Thor), god of thunder, and Zio (Tyr), whom Tacitus called "Mars". According to Herbert Schutz, most of their gods were "worldly", possessing form and having concrete relation to earthly objects, in contradistinction to the transcendent God of Christianity.