Umberto Eco, 1980. William of Baskerville investigating murders at a 1327 Benedictine abbey.
From Wikipedia
The Name of the Rose is the 1980 debut novel by Italian author Umberto Eco. It is a historical murder mystery set in an Italian monastery in 1327, and an intellectual mystery combining semiotics in fiction, biblical analysis, medieval studies, and literary theory. It was translated into English by William Weaver in 1983.