it was only in areas of dense Roman urbanization such as north Italy that a significant proportion of the population remained concentrated in towns, but these were now greatly reduced in size within their Roman walls and most had become the seat of dioceses and subject to the eleventh century, new settlements had appeared all over Europe, at trading or bridge points, on coasts (e.g. Venice), in the shelter of a castle (e.g. Prague) or at the gates of a monastery (e.g. Cluny.France).