Nobody actually knows what Elizabeth I died of but it could actually be simple old age as she was 69, a great age in Tudor times. There was no post mortem, so all we can do is theorise, but it may be that she died of blood poisoning after decades of using ceruse, the white face make-up she was so famous for, which contained lead, but it may also have been cancer, we just don't know. She did seem to sink into a depression after the execution of her favourite, Robert Devereux, Earl of Essex, and the deaths of close friends, so perhaps she also lost the will to live.
