When is the origin of the new period of Iranian history?

Thinking about the nature and quality of the periods that human beings have gone through or are going through in their history has been one of the concerns of philosophers, thinkers, historians and theologians. Hence, the history of the world is divided into different periods from different perspectives. The history of Iran is no exception to this rule. One of the most famous and common historical periodicals of Iran is its division into ancient, medieval and contemporary periods. The hidden point in these periodicals is to determine the origin of the new period of Iranian history. In fact, the question is whether Iran lacks a new era and has stepped directly from the Middle Ages to the contemporary era? If not, where is the origin of modern Iranian history and where does it begin and end? After evaluating the available data and criticizing the most important ideas in this regard, the article concludes that in the period of Iranian history, most of the controversy is over determining the origin of contemporary Iranian history and determining the origin of history. The new Iran is in a haze of ambiguity. The author then argues that for political, intellectual, social, and economic reasons, the new era of Iranian history begins with the Golestan Treaty at the end of the first period of the Iran-Russia wars and continues until the Constitutional Revolution, with the Constitution the beginning of the period. It is contemporary with Iran.