Short answers, pulled from the story.
The early modern period stretches from roughly 1500 to 1800 depending on the region studied. The year 1453 marked the fall of Constantinople, a moment that many historians cite as the starting point for the era.
Historian Lynn Thorndike first proposed the term early modern in his 1926 work A Short History of Civilization. The concept gained traction in economic history during the 1940s and 1950s before spreading to general history by the 1990s.
Nicolaus Copernicus published De revolutionibus orbium coelestium in 1543, marking the start of modern astronomy with his heliocentric cosmology. Isaac Newton published Principia Mathematica in 1687, establishing fundamental laws of physics that would dominate scientific thinking for centuries.
Martin Luther challenged the Church with his Ninety-five Theses in Germany, marking the start of the Reformation at the University of Wittenberg where he became a professor. The Peace of Augsburg in 1555 established the principle of cuius regio, eius religio, allowing rulers to determine their state's religion.
Ivan IV was officially crowned the first Tsar of Russia in 1547, transforming the country into a multiethnic, multiconfessional, and transcontinental state. He nearly doubled Russian territory during his long reign, adding Kazan and Astrakhan along the Volga River and Sibirean Khanate in South Western Siberia.