When did the Protestant Reformation begin?
Typically, the date given for the beginning of the Protestant Reformation is the year 1517 when Martin Luther posted his "95 theses" to the door of the Wittenburg cathedral, in which he decried the selling of plenary indulgences by the Catholic church. However, others had begun to criticize the Catholic church and advocate for reform much earlier; precursors, such as John Wycliffe and Jan Hus, were responsible for translating the bible into their native languages in England and Bohemia respectively, calling into question the scriptural basis for the institutions and doctrines of the Catholic church.
In what ways are Karl Marx and Hegel's philosophies alike, and how do they differ?
Karl Marx, who once was among the philosophers known as "Young Hegelians," agreed with the basic Hegelian theory that history has a teleology: an ultimate and ideal end-point to which it progresses. Where the two differ is with regard to the role of the material conditions (how humans interact with their environment, extract, and produce resources), and the role of the "superstructure" (e.g. ideologies of a political, religious, economic, or philosophical nature). Hegel considers the ideologies of the superstructure to be the driving force that governs and shapes mankind's material conditions throughout history. Marx, on the other hand, flips this model and holds that the material conditions are what shapes the ideologies of the superstructure.
What factor most contributed to the economic decline of the Ottoman Empire prior to the 19th century?
With the voyages during the Age of Discovery, European navigators and traders were able to establish trade routes to India and Asia, eliminating the Ottoman Empire's lucrative position as middlemen for overland trade between Europe, and Asia. Ultimately this lead to the Ottoman Empire being described as "sick man of Europe." Other events, such as nationalism leading to the independence of Balkan states formerly under Ottoman control, and the loss of WWI by the central powers would occur later, during the 19th and early 20th centuries respectively.