The Castle of Rohan , built over the period 1596 -- 1602 by Hercule de Rohan , Duke of Montbazon , is another visitor attraction .
It is now mostly in ruins .
The Castle of Rohan , built over the period 1596 -- 1602 by Hercule de Rohan , Duke of Montbazon , is another visitor attraction , although it is now mostly in ruins .