I'm more and more skeptical of historical narratives that portray the knowledge and practices of past peoples as a strict subset of our own knowledge. Along the same lines, we seem to constantly underestimate the peoples of the past (ex: the long-time assumption that the pyramid was built by slave labor[0]). We are absolutely more developed in some areas (sanitation, mechanization), but some things elude us.[1][2][3]
[0] http://news.discovery.com/history/ancient-egypt/pyramids-tom... [1] http://en.wikipedia.org/wiki/Damascus_steel [2] http://www.korean-arts.com/about_korean_celadon.htm [3] http://en.wikipedia.org/wiki/Roman_concrete