There is no documentary evidence for a daughter named Cecilia. She seems to have been invented in the nineteenth century when a portrait listed in an inventory of Knollys family belongings at Fernhill Park is recorded as ‘Cecilia Knollys, daughter to the Lord treasurer, afterwards Lady Leighton, 1580’  The author of the list, General Sir William Knollys, is reported to have qualified his identification claiming the paintings were hung too high for him to accurately read their identifications.
Elizabeth, Lady Leighton, has since then sometimes mistakenly been referred to as "Cecilia". A list of the Knollys children with their birth dates,written in Francis Knollys' own hand and discovered in one of his books, does not list a Cecilia. His last two children are named as Catherine and Dudley. Greet-49 08:51, 1 March 2020 (UTC)
Have you taken a DNA test? If so, login to add it. If not, see our friends at Ancestry DNA.
Cecilia is 14 degrees from Prince Philip, Duke of Edinburgh Mountbatten, 16 degrees from Grace de Monaco, 17 degrees from Henrik af Danmark, 33 degrees from Sālote Mafile’o Pilolevu Veiongo Tupou, 21 degrees from Liliu Loloku Walania Kamakaeha Liliuokalani Kapaakea, 19 degrees from Te Atairangikaahu Paki, 22 degrees from Bhumibol Adulyadej, 32 degrees from 慈禧 葉赫那拉, 11 degrees from Jan Sobieski and 26 degrees from Fionnuala O'Connor on our single family tree. Login to find your connection.