See also
| Partner: | William MACGYLOCHER (c. 1222-c. 1280) | |
| Partner: | (unknown) | |
| Children: | Donald I MACGYLOCHER (c. 1240-1297) | |
| Name: | William MACGYLOCHER | |
| Sex: | Male | |
| Father: | Duncan MACGYLOCHER (c. 1160-1244) | |
| Mother: | Orabella LATHERISK (c. 1175- ) | |
| Birth | c. 1222 | Mar, Aberdeenshire |
| Occupation | 5th Earl of Mar | |
| Death | c. 1280 (age 57-58) | |
| Name: | Donald I MACGYLOCHER | |
| Sex: | Male | |
| Spouse: | Elen 'the Younger' ferch Llewelyn of GWYNEDD (bef1230-1295) | |
| Birth | c. 1240 | Kildrummy Castle, Aberdeenshire |
| Occupation | 6th Earl of Mar | |
| Death | 7 Jul 1297 (age 56-57) | |
Uilleam was responsible for the construction of Kildrummy Castle, the greatest castle to have been built in 13th century northern Scotland. It is one of the few examples where a native Scottish magnate built a large-scale fortification, something normally practiced by the incoming French (Wikipedia).