What do you write in short if the exact date of birth has not been identified?
For example
"Danylo Bohdanovych Bratkovsky (the exact date of birth has not been identified – 26.11.1702) – public figure, writer. He comes from a long line of ancient Ukrainian nobility."

Nobody knows even circa when he was born. So, in brackets I've written "(the exact date of birth has not been identified – 26.11.1702)" but I guess there must be the better variant that would be more natural and shorter..

Thank you!!

Question

What do you write in short if the exact date of birth has not been identified?
For example 
"Danylo Bohdanovych Bratkovsky (the exact date of birth has not been identified – 26.11.1702) – public figure, writer. He comes from a long line of ancient Ukrainian nobility."

Nobody knows even circa when he was born. So, in brackets I've written "(the exact date of birth has not been identified – 26.11.1702)" but I guess there must be the better variant that would be more natural and shorter..

Thank you!!

Answer

I've frequently seen a question mark to indicate uncertainty for birth or death dates:
– Bratkovsky (1650?–1702) = date of birth uncertain
– Bratkovsky (?–1702) = date of birth unknown

Answer

you could say something like "believed to have been born in late 1702".