The royal chateau of Blois is interesting for its variety of styles ' ranging from the 13th to 17th centuries ' built around one central courtyard.
The château only uses 17th century styles. 
mnli hypothesis: The château only uses 17th century styles.  premise: The royal chateau of Blois is interesting for its variety of styles ' ranging from the 13th to 17th centuries ' built around one central courtyard.