What was Macbeth's first name?

The name Macbeth means 'son of life' and is a first name rather than a patronymic, hence the b is lower case. This is a very interesting site.
http://www.pathguy.com/macbeth.htm

Haven't managed to find his first name yet, but his father is recorded as being called Finback! Anyway, apart from all this Shakespeare stuff, the REAL Macbeth was a good king for his day - he lasted 17 years on the throne and managed to go to Rome on pilgrimage and not lose his kingdom while he was away. Have a look at

https://en.wikipedia.org/wiki/Macbeth,_King_of_Scotland

He came to the throne by a way quite legitimate in those days. The crown wasn't hereditary - so Duncan's sons had no real claim. The principle used was tanistry. There was a pool of nobles who were regarded as being eligible to rule, and one of them was chosen to succeed. OK, quite often the one that was chosen was the one that had done for his predecessor, but that was the way of it in other places too. Macbeth lasted 17 years, which is quite exceptional for then, and wasn't overthrown by a popular Scottish rising. He was toppled by an invasion by an 'English' army, but was buried on Iona in the traditional way of the Scottish Kings. And he was succeeded directly by his stepson, not by Malcolm. Only lasted a year or so though. Then the pro-English ways party got in. Macbeth was the last real Gaelic ruler of the old ways. Length of rule doesn't always mean a good ruler - look at Stalin! - but they were quite ready to rise up against a bad one in Scotland.

Actually, Macbeth (Shakespeare's or the real Scottish king) did not have a first name. "The St. Andrews Register renders his name in Latin as 'Macbet filius Finlach' which means Macbeth, son of Finlach." First names were not common in eleventh-century Scotland.

Source - Macbeth: Man and Myth, by Nick Aitchison (Sutton Publishing 2000).
https://www.amazon.com/Macbeth-Man-Myth-Nick-Aitchison/dp/0750926406