The origin of the name is possibly derived from the Old Norse, Kati's (a Viking personal name) outlying farmstead/hamlet (ON.thorpe). Caythorpe's Saxon name was believed to be "Kari-torp" meaning the settlement of the 'happy man'. It is not unusual for Old English and Viking elements to be intermingled reflecting the interesting mixture of peoples settling in the area. The Domesday Book entry in 1086 refers to the village of "Catorp." By then it was a settlement held by a Norman lord, Robert de Vesci, had two churches, a hall and a park, and was the proud owner of half a mill, which it shared with 'Fristun'. A map of 1576 shows the village name as 'Cathorpe', and eventually, after a few more spelling changes, it became 'Caythorpe'.
The Parish Church is dedicated to St Vincent, who was martyred at Valencia in AD303 under the persecutions of the Emperor Diocletian. He is often mistaken for the more famous St Laurence, who had also been martyred by torture on a gridiron over a fire, but in Rome in AD258. This church has the distinction of being one of only four churches in the country to be ascribed to St Vincent as patron. The other churches are Newnham in Hertfordshire, Littlebourne in Kent and Ashington in Somerset. Why a Christian martyr of the 4th century who lived and worked in the Saragossa district of Spain should be remembered at all in England is not clear, but his cult is ancient, and is widely mentioned in pre-Conquest calendars. The present Rector holds the view that his steadfastness would have gone down well with the Knights Hospitaller who, by a happy coincidence held the patronage when the church was built and that this martyr of 4th century Spain was thus honoured in Lincolnshire. Caythorpe was on the route be tween Newark and Temple Bruer where the Order had houses.
There is no trace of the two churches mentioned in the Domesday Book. It seems likely that we owe the building of the present magnificent church to Lady Elisabeth de Burgh, a niece of Edward II, who was very wealthy and owned the 'lordship' of Caythorpe and Frieston. Building started early in the 14th Century and was largely completed before the Black Death in 1348. Later additions in the 14th Century were the West Door and North Transept window.