If you search under 'John Dee' and 'spanish armada' on the web, you will find mention of John Dee (an Elizabethan Occultist) putting an 'Hex' on the Spanish armada' which caused it to founder. This is debatable.
However, John Dee was a spy for Queen Elizabeth. He travelled extensively in Europe and would have picked up snippets of information on his travels.
A search on his spying activities on the web may bring up some results.
There are a number of biographies of John Dee in print. However, his life is not a suitable topic for children.
I read once that his code name with Queen Elizabeth was '007', I cannot confirm this, and would love to know what the book was I was reading. The reference was to Ian Flemming and why he chose '007' for James Bond....