Do I add the last name when no last name was recorded in the source?
I found my ancestors in Norwegian church records from the early 1800's. On the birth and christening records, they give a first name of the child, but no last name. Following tradition from that time, the last name would have been based on their father's first name, addding -sen or -datter to his name. On Family Search, when I create a new record for this child, should I include the last name as I assume it would have been used, or leave it blank?