'Augustine was a highly credulous thinker': a tale of monsters and portents

I was reading today a book by Josie P. Campbell titled 'Popular Culture in the Middle Ages'. Here's what the author wrote about Augustine (p. 19):

According to Campbell, 'Augustine was a highly credulous thinker', not just credulous, but highly so. I felt rather favourable towards an exposition in support of this adventurous claim. Augustine wrote vigoro…