Aprirose has bought the De Vere Theobalds Estate Hotel for £24.2m from De Vere Hotels, owned by Starwood Capital.
Dating back to the 15th century, the Theobalds Estate in Cheshunt, Hertfordshire, includes 55 acres of gardens.
Manish Gudka, chief executive of Aprirose, said: “Our hotel business continues to go from strength to strength.