"Isaac newton was Sit Isaac Newton's real name.
no
"Sir." He was knighted.
If you meant 'last name,' then it is Newton. Sir is a title - like Mr. and Isaac is his first name.
Isaac Newton had no middle name
Sir Isaac Newton had no other name.
Isaac Newton
Sir Isaac Newton studied the nature of things.
English
The Newton Meter
Albert Einstein
1665 September
His Nationality is English.