Complex sentence: Berkhamsted Castle by tradition belongs to the eldest son of the reigning English monarch (presently Prince Charles) and is managed by English Heritage, under the Guardianship of the Secretary of State for National Heritage.
Split into simpler sentences: Berkhamsted Castle by tradition belongs to the eldest son of the English monarch, presently Prince Charles. The castle, is managed by English Heritage, under the Guardianship of the Secretary of State for National Heritage.