The following information is taken from the Dictionary of the Older Scots Tongue, available online at http://www.dsl.ac.uk/index.html. This is a work in progress.
| Spelling | Number | Dates & headers |
|---|---|---|
| Murdo | 1 | 1576 (craft) |
| Murdoch | 1 | 1599 (davach) |
| Murthou | 1 | 1428 (assith) |
| Murthow | 1 | 1391 (apportenant) |