pre-modern cultures, particularly those of Indo-European origin. Modern scholars, on the basis of Greco-Roman religious understanding, usually distinguish between sacred groves and trees, where a god is worshiped, and the worship of trees as divine (tree cult); it is unclear whether this distinction is valid for Germanic religion. Tacitus describes the ancient Germani as worshiping in sacred groves, including the grove of fetters of the Semnones and the grove where the Alcis were worshipped by the Nahanarvali. Tacitus mentions the following functions for Germanic sacred groves: the display of captured enemy standards and weapons, the keeping of the animal-shaped standards of the Batavii (Tac. hist. 4.22), and human sacrifice. Reconstructed Germanic words for sacred groves include *nimið-, *alh-, and *haruh-, which may have originally described different functions of the groves. Physical trees or poles could represent either a world tree, (Yggdrasil in Norse mythology), or a world pillar. Modern scholars describe such a sacred tree as an axis mundi ("hub of the world"), a center that runs along and connects multiple levels of the universe while also representing the world itself. In Roman Germania, columns depicting the god Jupiter as a rider are commonly found; they probably have a Celtic background and some connection to the notion of the world tree or column. One example of a sacred tree during the Middle Ages is the Oak of Jupiter purportedly felled by Saint Boniface in 724 CE in Hesse. Adam of Bremen mentions a sacred tree at the Temple of Uppsala, but the existence of this tree is controversial among scholars. It is also mentioned in Hervarar saga, and it may have been the central focus at the site and represented the world tree Yggdrasil. Further support for the existence of votive trees is provided by a birch root surrounded by animal skulls that was excavated at Frösö. Pagan Anglo-Saxon settlements often contained large standing poles, which were condemned as focuses of pagan worship by 6th-century English bishop Aldhelm. The Irminsul (Old Saxon great pillar) among the continental Saxons may have also been part of such a pole cult. Personnel and devotees Animal symbolism and warrior bands Post-conversion Norse texts mention dedicated groups of warriors, some of whom, the (berserkers) and , were associated with bears and wolves respectively. In Ynglinga saga, Snorri Sturluson associates these warriors with Odin. Many scholars argue that warrior bands, with their initiation rites and forms