I have been asked about the single most important artifact that I have seen. It is a single broken piece of pottery no bigger than a couple of inches, but its interpretation makes it one of the most significant artifacts in Jewish history. It is an inscribed potshard (a fragment of pottery) from Masada (in Israel) marked with the name "ben Yair." […] While it remains a single potshard marked in ink, it is a powerful symbol of what motivates archaeologists in the field: a simple object that signifies an entire historical event.
Source: wiktionary