He was styled Duke of Cambridge, but never formally created so, as he died aged one month.
At the time of Charles's birth, his uncle, Charles II of England, had no legitimate children and his queen consort, Catherine of Braganza, was reaching the age of 40 and it was clear that she would have no children and that the Duke of York would succeed as King.
[1] Because all of James's sons with his first wife, Anne Hyde, were dead, the newborn Charles was in direct line to the throne, a possibility that caused concern in England and Scotland because both James and Mary were Catholics and the majority of people wanted a Protestant monarch.
[1] Like so many of his brothers and sisters, the infant lived for a little more than a month, dying on 12 December the same year he was born.
During his short life, Charles bore a coat of arms, as a grandson of a British sovereign, consisting those of the kingdom, differenced by a label argent of five points ermine.