ANSWER: Leopold von Ranke
EXPLANATION: Leopold von Ranke was a German historian and also considered as the father of modern source-based history. He was the most important historian to shape historical profession as it emerged in Europe and the United States in the late 19th century. He was able to implement the seminar teaching method in his classroom and focused on archival research and analysis of historical documents. He set the standards for much of later historical writing, introducing reliance on primary sources, emphasized on narrative history and especially international politics.