Niccolo and Maffeo were away for many years. It was not unusual for merchants to trade in other countries and not come home for a long time. Travel was often very dangerous and some merchants never made the long journey back to their families.
We do not know a lot about Marco when he was a child. Who was his mother? Did he have any brothers or sisters? Nobody really knows. But we can imagine that he had a very comfortable early life. We know that he learned to read and write the Italian of his time and also use numbers. As the son of a rich merchant family he possibly went to church school or perhaps a teacher came to his house.