what 'being' means

I can’t get what ‘being’ means in this sentence:“My family name being Pirrip, and my first name Philip, I could make of both names more than Pip.”
Could please someone explain it to me?
Thanks in advance

It’s another way of saying:
As my family name was Pirrip

The character’s name is Philip Pirrip, but as a young child he could not manage to say that, so instead he run them together and called himself ‘Pip’ - which is how he got that nickname.