Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The personal name Duncan can be found in Scotland s oldest records in its Gaelic form Dunchad/Donchadh/Donachie/Donnchadh and other spelling variants. (Dunchad) Duncan, originally a forename is without doubt one of the earliest names in Scotland surnames being introduced by the Normans around 1120 AD and originates from the Dalriadan Celtic Celtic Scotii (Scots) from Ireland who colonised the south west of Scotland from about the 4th century AD. Dúnchad (Duncan mac Conaing co- ruled Dalriada with Conall II (c.650 - 654).