1. If part of the name, you don't use "the." King Agememmon.
3. "The Greek King, Alexandros." You are naming the office, then specifying the name of the officeholder.
4. Optional. If you mean it as his title, don't use "the." Diana, Princess of Wales. If you mean it as a description, use it. Obama, the President of the US.
5. No. Most countries don't use articles.
- For Teachers