Abstract
The Braudel thesis predicts that in the Early Modern Period, when travel over sea was much more efficient than over land, seas like the Mediterranean, which are surrounded by different states, acted as natural political and military boundaries between these states, but also linked them through trade, travel and transport. In the proposed project this idea is tested for the North Sea in the period of Amsterdam's greatest flourishing. A database containing empirical data on trade, fishing, migration and economic prosperity for all regions surrounding the North Sea will be constructed. On the basis of this and additional research four dissertations and a synthetical book on the North Sea regions in Amsterdam's Golden Age will be written.