What is the setting in the novel, Hobby?

In Hobby, Merlin travels from the New Forest through an area of ancient ruins to a medieval trading center. There, he joins the company of Ambrosius and Viviane. Yolen takes care to depict an authentic May fair and to depict the people and buildings as they would have appeared in Merlin's day.

The problem of a tower collapsing because of leaking Roman plumbing underneath is a nice touch, because the people of the era would have had to work with Roman plumbing and buildings in most cities of Romanized Britain. The Romans would have abandoned Britain less than a generation before the events in the novella.