During the Tudor period the Reformation produced a gradual shift to Protestantism, much of London passing from church to private ownership. The traffic in woollen cloths shipped undyed and undressed from London to the nearby shores of the Low Countries, where it was considered indispensable. But the tentacles of English maritime enterprise hardly extended beyond the seas of north-west Europe. The commercial route to Italy and the Mediterranean Sea normally lay through Antwerp and over the Alps; any ships passing through the Strait of Gibraltar to or from England were likely to be Italian or Ragusan. Upon the re-opening of the Netherlands to English shipping in January 1565, there ensued a strong outburst of commercial activity. The Royal Exchange was founded. Mercantilism grew, and monopoly trading companies such as the East India Company were established, with trade expanding to the New World. London became the principal North Sea port, with migrants arriving from England and abroad. The population rose from an estimated 50,000 in 1530 to about 225,000 in 1605.