This is a paid asset, but now you can download Medieval Castle Free.
Detail this asset from Unity Store: Original Link
Start building your own medieval kingdom quickly with this great new model set! It includes a range of lovingly crafted modular castle components that can be used to create all sorts of castle big or small castle designs. You also get a .Unitypackage to get started!
Included pieces are: -Central Fort. -Castle Gate. -Fountain. -2 Castle Towers. -Rotunda. -Bridge. -2 walls. -3 Rocks. -Vegatation (2 trees,Grass,Foliage). -Props (Flags,Torch, Shed,Door).