History (from Greek ἱστορία, historia, meaning "inquiry; knowledge acquired by investigation")^[2] is the study of the past.^[3][4] Events occurring before the invention of writing systems are considered prehistory. "History" is an umbrella term that relates to past events as well as the memory, discovery, collection, organization, presentation, and interpretation of information about these events. Historians place the past in context using historical sources such as written documents, oral accounts, ecological markers, and material objects including art and artifacts.