Apparently, in 1921, during digging to expand a rail line, excavators found the original Roman wall of the ancient town of Bordeaux, France. The wall was dated at about 300 C.E. Some of the stones and elements used to build the wall were found to have value beyond wall-building material, as they included things like this altar to a goddess named Boudicca (Boudiga is the ancient Welsh version of her name), which was determined to have come from Britannia many years prior to its use in the wall. This may be a cult devoted to her which developed after her death; the maker of the altar erected it in gratitude for a safe sea passage from Britannia. There is some suggestion, however, in some sources that the original Boudicca herself was in fact a Druid High Priestess rather than a queen or princess of the Iceni.
The goddess is called Tutela Boudiga. There is apparently a copy of the altar in the British Museum; I can't find the original online.
Latin Inscription: Deae Tutel(a)e Boudig(ae) / M(arcus) Aur(elius) Lunaris se / vir Aug(ustalis) col(oniarum) Ebor(aci) et / Lind(i) prov(inciae) Brit(anniae) Inf(erioris) / aram quam vover(at) / ab Eboraci avect(us) / v(orum) s(olvit) l(ibens) m(erito) / Perpetuo et Corne(liano consulibus).
Translation: In honour of the goddess Tutela Boudiga, Marcus Aurelius Lunaris Sevir Augustalis of the coloniae of York and Lincoln, in the province of Lower Britain, [set up] the altar which he vowed on starting from York. Willingly and rightly did he fulfil his vow, in the consularship of Perpetuus and Cornelianus.
