In spite of the fog, this image shows that the castle, still a working building, evolved over centuries.
The tower on the left, with the weathervane, is the John O'Gaunt Gateway, built in 1405. The tower in the middle is the Governors' House, added between 1788 and 1823. The one to the right, superficially similar in this light, is the Well Tower (aka Witches' Tower), built in the 12th/13th century and hence one of the oldest parts of the complex.