Dido (singer) was born on Christmas Day, she also celebrates an "official birthday" on 25 June, following the example of Paddington Bear. Her mother, Clare (née Collins), is a poet of French ancestry, and her father, William O'Malley Armstrong (1938–2006), was an Irish publisher and former managing director of Sidgwick & Jackson. Her elder brother, Rowland Constantine O'Malley Armstrong, is better known as record producer Rollo, part of the British electronica trio Faithless. Despite their birth names, the pair were known from childhood by the names Dido and Rollo and Dido considers this as her real name, and not simply a stage
Rollo presumed to be a latinisation of the Old Norse name Hrólfr – a theory that is supported by the rendition of Hrólfr as "Roluo" in the "Gesta Danorum". It is also sometimes suggested that Rollo may be a Latinised version of another Norse name, "Hrollaugr". Rollo is generally identified with one Viking in particular – a man of high social status mentioned in Icelandic sagas, which refer to him by the Old Norse name Göngu-Hrólfr, meaning "Hrólfr the Walker". ("Göngu-Hrólfr" is also widely known by an Old Danish variant, "Ganger-Hrolf".) The byname "Walker" is usually understood to suggest that Rollo