It is easy to find maps showing the various romance dialects that used to be spoken in France, and indeed many romance dialects are still spoken today in Italy. My question is this. Were there distinct boundaries between adjacent romance dialects, or was it in practice more of a continuum? And if there were distinct boundaries eg one village speaks X, the next village speaks Y, what preserved or enforced this separation? Note that I am talking about dialects in the past, before a standard French was imposed. Clearly today languages tend to be defined by geopolitical boundaries, thus Basque has survived due to geographical inaccessibility, and might have been far more widely spoken in the past.