Royal titles are much more complicated than many might think, with some of the Queen's great-grandchildren being princes and princesses and others not.
Most notably, the three children of Zara Tindall do not hold the titles. Zara, 40 is the daughter of Princess Anne and her ex-husband Captain Mark Phillips.
Zara married former rugby player Mike Tindall, 43 and took his last name and the couple have three children together, Mia, Lena and Lucas.
However none of the three are hold the title of Prince or Princess like some of the Queen's other great-grandchildren. The reason that they do not hold the titles is simple, they come through a female bloodline, therefore making them ineligible for HRH status.
Read more on ok.co.uk