Globalization refers to the expansion and intensification of social relations and consciousness across world-time and world-space.
Manfred Steger, Globalization (2010), 18.
Why a prehistory of globalization? The nature of globalization is so vexing a topic that the wary avoid defining the term much as they would avoid the bubonic plague. By comparison, the historical boundaries of globalization are pretty well agreed upon. It first took shape around 1500 AD, along with the Age of Exploration. Rendering the study of globalizaton even more vexatious by drawing upon "prehistoric" information would seem to be just asking for trouble.
And yet, the effort is manifestly worth making. For one thing, far more attention has been devoted to what globalization is, and what it may become, than to what globalization has actually been. Traditionally, globalization is said to have started around 1500 AD, along with the Age of Exploration. There is an undeniable connection, but the Age of Exploration itself did not just spring forth from a vacuum. Neither, I submit, did globalization.
Scholars have done a lot of important work of finding isolated "globalizations" around the world. But the assumption that "globalization" has existed for more or less five centuries has impeded investigators from seeking out isolated "globalizations" over the course of the fifty-five or so centuries which preceded. Apparently globalization transcends boundaries of space, but not necessarily of time. This is mistaken. Again, globalization did not spring forth from a vacuum. Hence this attempt at a prehistory of globalization.
This diachronic approach of examining all of historical time for signs of globalization will certainly not displace the comparatively synchronic approach of studying the last five centuries. After all, no sane person would suggest that the ancient empires of Egypt, Sumer, Persia, Macedon, or Rome literally shrunk the world the way that modern technology has. But even if it turns out that the ancient world has little or nothing to offer the study of globalization, this too would be a contribution.