Columb John (today "Columbjohn") in the parish of Broadclyst in Devon, England, is an historic estate and was briefly the seat of the prominent Acland family which later moved to the adjacent estate of Killerton. Nothing of the structure of the Acland mansion house survives except the arch to the gatehouse, dated about 1590, and the private chapel, restored in 1851. The site of the former mansion house is situated one mile due west of Killerton House, and five miles north-east of the historic centre of the City of Exeter. The estate's name derives from it having been held by the Culme family, whose own name was taken from its landholdings in the vicinity of the River Culm, which flows through the Columb John estate.
The Devon Domesday Book tenant-in-chief of Colum in 1068 was Fulchere, also known as "Fulchere the Bowman", one of the king's lesser tenants. He held it in demesne. Most of his seven holdings listed in the Domesday Book later passed to the feudal barony of Plympton, of which the lords were later the Courtenay Earls of Devon.
The Culme family name was taken from its landholdings in the vicinity of the River Culm, which flows through the Columb John estate. A branch of the Culme family was later seated at Molland Champson in North Devon. The descent of the estate in the de Culm family is given by Pole (d.1635) as follows:
In 1295 Clifford St Aubyn and Sir Mauger St Aubyn were tenants of Columb John under the Clifford family.
In 1314 Columb John was held by Sir Gilbert de Bere, in right of his wife Isabell Clifford, daughter of Roger Clifford.
The Prideaux family is believed to be of Norman origin and to have first settled in England at some time after the Norman Conquest of 1066 at Prideaux Castle, near Fowey, in Cornwall. It abandoned that seat and moved to Devon, where it spread out in various branches, most notably at Orcharton, Modbury; Adeston, Holbeton; Thuborough, Sutcombe; Solden, Holsworthy; Netherton, Farway; Ashburton; Nutwell, Woodbury and Ford Abbey, Thorncombe. Another branch built Prideaux Place in Cornwall in 1592, where it survives today. It was one of the most widespread and successful of all the gentry families of Devon, and as remarked upon by Swete (d.1821), exceptionally most of the expansion was performed by younger sons, who by the custom of primogeniture were expected to make their own fortunes.