The first archaeologists could be called "treasure hunters." They valued the beautiful objects that could be found underground. But by the start of the 20th century, a more scientific approach was the rule. Objects found in an identifiable layer can reveal many facts about the people who left that layer behind.

When Heinrich Schliemann started working at Troy in 1870, like most of us, he did some things right and others not so right. Here's what he did right:

- Take detailed notes
- Take Photographs
- Hire specialists to map, draw and analyze
- publish the results!

Schliemann was confused about the time frame for all the Troy levels. His architect and successor, Wilhelm Doerpfeld, figured out the relative time frame through careful observation and comparison to other sites

he knew well in Greece: Mycenae, Olympia, and Tiryns.

Carl Blegen, in the 1930s, benefited from the work of those who came before. Using that as a basis, he was able to make finer distinctions in the layers, what we call stratigraphy. Blegen took hundreds of photos, but he also used a tool new to his time: the movie camera.

Archaeologists invented some important new tools after World War II, so Schliemann, Doerpfeld and Blegen could not have taken advantage of methods like Carbon 14 dating.

Nowadays, if the conditions are right, archaeologists can see below the surface with various electronic scanning devices. The Troy VIII street grid and the Troy VI outer fortifications were found without digging more than a few trenches to check the results!