A timeline of historical heads of state, within the context of modern national boundaries.
A few notes:
- Names and dates are based on information from Wikipedia. Links to individual biographical articles in Wikipedia are included when available. On rare occasions, sources outside Wikipedia were used to clarify dates and historicity. Judgments regarding who to include or exclude in this timeline, and which dates to use, have been made at my own discretion based on the information available on Wikipedia.
- Timelines for individual nations begin with the earliest historical state leader I was able to identify on Wikipedia. I have considered a leader historical if he is recorded in contemporary sources, thus attesting to his identity and date. In some cases, when historical records are incomplete or absent, I may occasionally include a more legendary figure in the list of heads of state, if he or she is generally considered historical; however, each timeline is intended to begin with an attested historical figure.
- In some governmental formats, there is a distinction between head of state and head of government, for example in the United Kingdom where the monarch is the head of state, and the Prime Minister is the leader of the state government. This timeline lists heads of state in cases where there is such a distinction.
- Typically throughout history, there has been more than one group, tribe, or nation simultaneously occupying the territory represented by modern national boundaries, each with its own leaders. For the purposes of this timeline, I limit myself to one political entity per country for any point in time. Generally, I make this determination based on: 1) if a leader was considered the predominant figure or wielded the most authority over the other peoples within the modern national territory; 2) a general preference toward those groups who predominated in the traditional heartland of the modern country, and; 3) historical continuity with the social and political development of the modern nation.
- When the leadership of a state is contested or unclear, I try to represent the facts on the ground as they would have been understood by contemporaries, based on the historical evidence available on Wikipedia. Thus, I may list a de facto head of state, as opposed to a presumed de jure head of state, when interpretations of the legality or legitimacy of certain leaders appear subject to historical revisionism.
- Sometimes information on Wikipedia is updated, and it is possible to improve or correct the information represented in this timeline. I do not intend to spend too much time updating the research I have performed to date in putting this timeline together. Rather, I prefer to spend time expanding the timeline to more countries. Perhaps when I finish the rest of the world, I will return to make edits.