From 1846 to 1848, Cassiobury House temporarily became a royal residence when the Dowager Queen Adelaide, widow of King William IV, took up residence here. Suffering from chronic illness, Adelaide often moved her place of residence in a vain search for health, staying at the country houses of various British aristocracy. After living for a short time at Witley Court in Worcestershire, she came to Watford and rented Cassiobury. During her time here, she played host to Queen Victoria and Prince Albert. Within three years, Adelaide had moved on again, taking up residence at Bentley Priory in Stanmore.