"stands wrapt in thicker darkness."
"The sense of the word, and with it any sure insight into the significance of her being, are locked up from us."Grimm does however have this to say about Tanfana's temple:
"In all probability the sanctuary of Tanfana which Germanicus demolished in AD. 14 was not a mere grove, but a real building, otherwise Tacitus would hardly have called the destruction of it a 'levelling to the ground'.
"If the Tanfana temple could be built by Germans, we can suppose the same of the Alamann, the Saxon and the Frisian temples; and what was done in the first century, is still more likely to have been done in the 2nd, 3rd, and 4th."
Saussaye in his The Religion of the Teutons concludes that from the timing of the festival (autumn) that She must be a Goddess of fertility and of the soil.
The fact that Tanfana was worshipped in a temple is a direct contradition of a statement he made in Germania:
"In other matters, they judge it not in accord with the greatness of the gods to confine them with walls or to liken them in appearance to any human countenance. They consecrate woods and groves, and the mystery that they see only in their awe: they call by the names of gods." (9.1, Rives)
"The Germans do not think it in keeping with the divine majesty to confine gods within walls or to portray them in the likeness of any human countenance. Their holy places are woods and groves, and they apply the names of deities to that hidden presence which is seen only by the eye of reverence." (9, Mattingley, Handford)
In Germania 40.3 Tacitus refers to the temple of the Goddess Nerthus. I do not doubt that predominately the ancient Teutons did worship the Gods in groves and woods but there is always the exception to the rule and practices did change where there was cultural interchange with other peoples such as the Celts and Romans and obviously things do change over the course of time. Adam of Bremen refers to the temple at Uppsala but obviously this is strictly speaking in Scandinavia, not Germania. Bede in his A History of the English Church and People (Chapter 13) refers to an Anglo-Saxon priest called Coifi who after converting to xtianity desecrated the statues of the Gods, which were housed in a temple. We also know that Pope Gregory instructed Augustine not to destroy the heathen temples of the English:
"....we wish to inform him that we have been giving careful thought to the affairs of the English, and have come to the conclusion that the temples of the idols among that people should on no account be destroyed. The idols are to be destroyed, but the temples themselves are to be aspersed with holy water, altars set up in them, and relics deposited there." (Bede, Chapter 30, Sherley-Price, Latham)
Gregory was being practical as if the temples are "well built" they could be utilised by the church, and the people were accustomed to going there to worship the ancient Gods. This is why many old English churches may be found on the sacred sites of old places of heathen worship. Clearly temples in Anglo-Saxon England were common place.