The reigning Queen of the United Kingdom is Elizabeth II (Elizabeth the second). There is no "Queen Elizabeth the 4th" or Queen Elizabeth IV at the current time, nor any immediate prospect of one.
Prince Harry is Queen Elizabeth's fourth eldest grandchild.
Queen Elizabeth II is not. Queen Elizabeth the Queen Mother was.
King George VI's wife was Queen Elizabeth. Most people alive today would know her by the title she took after George VI's death - Queen Elizabeth, the Queen Mother. This was specifically done because her given name and that of her daughter were both Elizabeth, and this was an easy way of differentiating them. She was born The Lady Elizabeth Bowes-Lyon, fourth daughter of the Earl and Countess of Strathmore and Kinghorne, a Scottish noble family.
When did Queen Elizabeth Die?
Queen Elizabeth I was crowned in 1559, Queen Elizabeth II was crowned in 1953.
If you refer to a British coin, or any commonwealth coin using the Fourth Portrait of Queen Elizabeth II, it says IRB, not RIB. Ian Rank-Broadley is the designer of the Fourth portrait bust of Queen Elizabeth II.
Her Majesty Queen Elizabeth does not have nicknames.
No. Queen Elizabeth II is the English queen
Queen Elizabeth is English.
Regnal numbers, I II, IV etc are only applied to the Monarch. If the Monarch's spouse is a female then she automatically becomes Queen Consort. Hence: Queen Elizabeth I, followed by Queen Elizabeth the Queen Consort and then Queen Elizabeth II. When Queen Elizabeth II ascended to the throne Queen Elizabeth became Her Majesty Queen Elizabeth the Queen Mother a title afforded to her by Queen Elizabeth II
Queen Elizabeth 1
Queen Elizabeth II's Mother was Her Majesty Queen Elizabeth Angela Marguerite Bowes-Lyon, The Queen Mother.