Aquae Sulis Western Roman Empire and its urban life declined. However, while the great suite of baths fell into disrepair, some use of the hot springs continued. After the end of Roman rule in Britain around AD 410, some residents seem to have remained, but violence seems to have taken root for, in the 440s, a young girl's severed head was thrust into an oven in Abbeygate Street. As far back as Geoffrey of Monmouth, the Arthurian Battle of Mons Badonicus (c. 500) has been suggested to have taken place near Aquae Sulis. In medieval times, the Roman temple at Bath was
Aphanizomenon flos-aquae (dietary supplement) from the air, and water to synthesize proteins, carbohydrates, and lipids. AFA is also able to directly use molecular nitrogen from the air to produce proteins and other nitrogen-containing biomolecules. This ability is widespread in prokaryotes, but unknown in eukaryotes. "Aphanizomenon flos-aquae" as a species has both toxic and non-toxic forms. While benefits have been indicated, toxicity has been shown in some strains of the species "Aphanizomenon flos-aquae", with cylindrospermopsin and saxitoxins present, and microcystins found contaminating AFA dietary supplements. The World Health Organization's "Guidelines For Drinking Water Quality" note Anatoxin-a, saxitoxins, and cylindrospermopsins are present in the Aphanizomenon genus.