LONDON — Prince George started at Eton College on Tuesday, as the future British king followed in the footsteps of his father, Prince William, the heir to the throne, by attending the prestigious 600-year-old school.The 13-year-old grandson of King Charles was joined by his parents, William and Kate, the Princess of Wales, for his arrival at his new school, with video showing them smiling and looking relaxed as they were greeted by Eton’s head teacher, Simon Henderson.Both his father and George’s uncle Prince Harry attended Eton, one ​of Britain’s most elite schools, which is located close ​to the monarch’s Windsor Castle, west of London, and where William and his wife, Kate, and their other two children, Charlotte and Louis, also have a home.Fees for the all-boys boarding school, which was founded by King Henry VI in 1440, ​are about $88,000 a year.George, the second in line to the throne, was previously at the private Lambrook School also near ​Windsor with his sister and younger brother.