Quotation from Cassiobury Park page in Wikepedia:-
" Caesegsho and Cashio are earlier names for the area or for the hamlet that existed in the area. The name "Caegesho" referred to a larger area of land granted by Offa to the Abbey of St Albans in 793. "Caeg" (Old English cæg) may have been a man's name, while Old English ho means "a spur of land" (see Hoo). It was spelled "Caissou" or "Chaissou" in the 11th century and gradually evolved into "Cassio". The suffix "-bury" occurs in many English place names. It comes from the Old English word for a fortified place, burh, whose dative, byrig, means "by the fort", or "by the manor".
Using the zoom facilities of your browser will enable you to see the locations of the 8 Manors within Albanstow -Later called Cashio number 7 is the manor of Cassio.
1 St. Paul's Walden
3 St. Albans
4 Hanstead (House)
Information below is from the Phillmore Domesday Book (ed. John Morris) (Hertfordshire) 1976; ISBN 0 85033 137 4).
Its map (drawn by Jim Hardy) of the county shows the 1086 boundaries of the hundreds where Cashio Hundred is identified with a capital C.
Below are the 11th century Latin and translated texts for Cassio manor from the Phillmore Domesday Book (Hertfordshire). While the units of measurement are archaic they can be usefully translated. For example:-
In CASHIO Hundred “Albanstow”
Cassio (as with many historic names spelling varies) in many people’s minds is Cassiobury, but Cassio (with its several old spellings) is the root of the names of both a much larger area, Cashio Hundred (called “Albanstou” in the “Domesday Book”), and a manor called Cassio within it.
Modern Cassiobury is the area at the northern end of Watford High Street. Its name is derived from the ancient names for the land and the people who once lived there. However its exact location, in ancient times is unclear. A Roman track way is thought to have passed through it.
The Cassi were a tribe existing at the same time as the Iceni (Boudicia's tribe) who lived in what is now known as Buckinghamshire, Bedfordshire and Hertfordshire.
The map the top right corner of the gallery below “A Mapp of Hartfordshire” by Richard Blome, 1673 contains the name “TRINOBANTES” (also spelled Trinoventes) who the Encyclopeadea Britannica identifies as their tribe, who, under their leader Cassivellaunus (also spelled Cassivelaunus), waged a guerilla war against the Romans in the first century BC.
The Abbot holds Rickmansworth himself. It answers for 15 hides. Land for 20 ploughs. In lordship 5 hides; 3 ploughs there; a further 2 possible.
4 Frenchmen and 22 villagers with 9 smallholders have 14 ploughs; a further 1 possible. 5 cottagers; 5 slaves. 1 mill at 5s 4d; meadow for 4 ploughs; from fish, 4s; pasture for the livestock; woodland, 1200 pigs
Total value £20 10s; when acquired £12; before 1066 £20. St. Albans held and holds this, manor in lordship.
The Abbot holds Cassio himself. It answers for 20 hides. Abbot holds 19 of them. Land for 22 ploughs. In lordship 6 hides; 5 ploughs there; a sixth possible.