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 samples exceeded the safety value of 1 µg microcystin per gram. University professor Daniel Dietrich warned parents not to let children consume "A. flos-aquae" products, since children are even more vulnerable to toxic effects, due to lower body weight, and the continuous intake might lead to accumulation of toxins. Dietrich also warned against quackery schemes selling these cyanobacteria as medicine against illnesses such as attention deficit hyperactivity disorder, causing people to omit their regular drugs. A Canadian study studying the effect of "A. flos-aquae" on the immune and endocrine systems, as well as on general blood physiology, found that eating