obvious. Archaeological evidence is also extensive, including evidence from burials and sacrificial sites. Ancient votive altars from the Rhineland often contain inscriptions naming gods with Germanic or partially Germanic names. Secondary sources Most textual sources on Germanic religion were written by outsiders. The chief textual source for Germanic religion in the Roman period is Tacitus's Germania. There are problems with Tacitus's work, however, as it is unclear how much he really knew about the Germanic peoples he described and because he employed numerous topoi dating back to Herodotus that were used when describing a barbarian people. Unlike some other Roman authors, Tacitus had not visited Germanic territories. Furthermore, Tacitus' reliability as a source can be characterized by his rhetorical tendencies, since one of the purposes of Germania was to present his Roman compatriots with an example of the virtues he believed they were missing. Julius Caesar, Procopius, and other ancient authors also offer some information on Germanic religion. Textual sources for post-Roman continental Germanic religion are written by Christian authors: Some of the gods of the Lombards are described in the 7th-century Origo gentis Langobardorum ("Origin of the Lombard People"), while a small amount of information on the religion of the pagan Franks can be found in Gregory of Tours's late 6th-century ("History of the Franks"). An important source for the pre-Christian religion of the Anglo-Saxons is Bede's Ecclesiastical History of the English People (c. 731). Other sources include historians such as Jordanes (6th century CE) and Paul the Deacon (8th century), as well as saint lives and Christian legislation against various practices. Textual sources for Scandinavian religion are much more extensive. They include the aforementioned poems of the Poetic Edda, Eddic poetry found in other sources, the Prose Edda, which is usually attributed to the Icelander Snorri Sturluson (13th century CE), Skaldic poetry, poetic kennings with mythological content, Snorri's Heimskringla, the Gesta Danorum of Saxo Grammaticus (12th-13th century CE), Icelandic historical writing and sagas, as well as outsider sources such as the report on the Rus' made by the Arab traveler Ahmad ibn Fadlan (10th century), the Gesta Hammaburgensis ecclesiae pontificum by bishop Adam of Bremen (11th century CE), and various saints' lives. Outside influences and syncretism Germanic religion has been influenced by the beliefs of other cultures. Celtic and Germanic peoples were in close contact in the first millennium BCE, and evidence for Celtic influence on Germanic religion