The very first Duke of Cambridge was the eldest nephew of the king, Charles Stuart but he sadly died aged just six months old. The next in line was his younger brother, James Stuart but tragedy struck again when the young royal died of what is believed to have either been smallpox or the bubonic plague.
The King then made his third oldest nephew, Edgar Stuart, the Duke of Cambridge but he died at the age of three. And next in line for the ill-fated title was their younger brother, Charles Stuart, who also passed away very young at just 35-days old.
Perhaps unsurprisingly the title was not used again until 1706 when Queen Anne made the future King George II the fifth Duke of Cambridge. The title was then given by King George III to his seventh son, Prince Adolphus. It then passed to the prince’s son, Prince George and became extinct after his death as his marriage had violated The Royal Marriages Act of 1772.

The heir to the Dukedom of Cambridge is currently Prince George, but whether he will ever inherit the title or not depends on when his father inherits the throne and when he eventually marries. If George becomes the Prince of Wales earlier than expected, it is possible that Louis could become the next Duke of Cambridge.
But if George inherits his father’s current title, Louis could get a different royal title, the Duke of York, which is traditionally held by the second son of the monarch. But this would of course depend on what happens to Prince Andrew. Previous Dukes of York include the late Queen’s grandfather, King George V and her father, George VI, meaning she was known as Princess Elizabeth of York until her father became the king in 1936.