The past and its investigation involves the study of evidence from sources to build an understanding of past places, people and events. History, archaeology and science contribute to this process. These techniques play different roles in the process of investigating the past. .
Contributing to the investigation of the past, through written sources, is history. Historians use written sources in association with archaeological and scientific evidence in order to create possible situations that may have occurred, allowing us to get a much better understanding of the past. In the study of Alexander the Great's drinking problem, only written sources were used. The involvement of both science and archaeology were hardly used. Written sources such as The History of Alexander, Plutarch's Lives, Plutarch, Arrian, Quintus Curtius Rufus and the Campaigns of Alexander contributed to the involvement of modern historian J.M O'Brien. This use of sources by historians helps provide a greater understanding into the past. .
Archaeology also contributes to the investigation of the past through the study of artifacts; including human or manufactured objects. The case study shown on the first Pharaoh of united upper and lower Egypt presented us with archaeological evidence of the 'Narmer Palette' as well as written evidence. In this case the evidence provide different in the form of the Palette, a piece of primary evidence, and written sources by Aegyptiacia; and Diodorous Siculus, Mantheo, The histories; disagreed upon the name of the pharaoh, the palette naming him Narmer" and other sources as Menes. To gain a true understanding of the case and the dependability of the sources has to be analysed. Based on the palette being a primary source, but also having two other sources contradictory with it, it was decided that at the time the name was both Narmer and Menes and that the considerable time difference between the event and the secondary sources had changed the name used.