From Linda Finley Rogers-Fefferman research on a proposed lineage for descent from MacBeth (but one which lacks any credible source citations, other than for MacBeth's ancestry):

http://archiver.rootsweb.ancestry.com/th/read/SCOT-DNA/2006-04/1144015544

2. Macbeth / MACBETH MAC FINDLAECH

Macbeth's pedigree, in MS Rawl B. 502, a believed reliable source of genealogies, shows his descent from Ferchair, who held the kingship of Dalriada in the late seventh century.

MACBETH's death ended a dynasty (Ireland and Scotland). At the time of his death, his children were young, so the Clan FIONNLAGH placed his stepson, LULACH, on the throne. He only reigned 6 months, being defeated and slain at Eske in Strathbogie by the Saxon invaders and the rebellious adherents of Malcolm CANMORE.

After LULACH, no other member of the Clan FIONNLAGH has been on the throne of Scotland to the present day. Members of the clan became hunted outlaws, long before religious persecution drove them from the British Isles. And this may be reason why some changed their names.

3. MacBeatha McFinlay

• b. 1045 Cromarty, Ross and Cromarty, Scotland;
• d. 1093 Cromarty, Ross and Cromarty, Scotland;
• md. 1079 Bethoca McBrad daughter of Andrew McBrad

MacBeatha McFinley, Thane of Cromarty; (b. bef. 1057 in Cromarty ; d. 1093) Married Bethoca, daughter of Andrew McBrad (McBride.)

Macbeatha McFinlay, a younger son of Macbeth, was 1060-1093, Thane of Cromarty; married Bethoca, daughter of Andrew McBrad (McBride.)

4. Ruari (Rory) McFinlay

• b. 1080 Cromarty, Ross Cromarty, Scotland (source Patricia GUINIVAN Apt. 19 767 Springfield Avenue Summit, NJ 07901 as per FamilySearch.Com)
• Thane of Crumbacty (Cromarty), 1100 to 1152

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Unknown source:

• Surname: McFinlay
• Given Name: Macbeatha
• Suffix: Thane of Cromarty
• Sex: M
• Birth: Thane of Cromarty 1060-1093 AD
• UID: 4519647509B1D511AF308ED0115A3E743190

Children:

• 1. Has Children Ruari MCFINLAY Thane of Cromarty b: Thane of Cromarty 1100-1152 AD