Research into ego-documents has being going on around the world for several decades, especially in continental Europe. The Dutch historian Jacques Presser, the inventor of the term, used "ego-document" to refer to materials such as diaries, memoirs, autobiographies, and personal letters. The term was first used in the English language by Peter Burke. Some groups of historians, such as the one in Berlin under the leadership of Claudia Ulbrich, prefer to use the term "self-narrative" instead. Kaspar von Greyerz, leader of the Basel team and a leading critic, considers the term "ego-document" an unfortunate one on account of its connotation of Sigmund Freud's concept of ego. He claims that early modern material does not reflect the inner psychological state of the writer but rather the formal, outward facade. Artificial periodization prevents us from understanding the nature and intellectual heritage of the human being. The question is, "What changed with the transition from premodern to modern when suddenly characters started to see themselves as historical figures worth talking about?"