The whole process of liberation progressed by a series of imperceptible acts of devotion to the common cause, accomplished by men who came out of the masses--by unknown heroes whose very names have not been preserved by history. The wonderful movement of the God's peace (treuga Dei) by which the popular masses endeavoured to put a limit to the endless family feuds of the noble families, was born in the young towns, the bishops and the citizens trying to extend to the nobles the peace they had established within their town walls.(19) Already at that period, the commercial cities of Italy, and especially Amalfi (which had its elected consuls since 844, and frequently changed its doges in the tenth century)(20) worked out the customary maritime and commercial law which later on became a model for all Europe; Ravenna elaborated its craft organization, and Milan, which had made its first revolution in 980, became a great centre of commerce, its trades enjoying a full independence since the eleventh century.(21) So also Brugge and Ghent; so also several cities of France in which the Mahl or forum had become a quite independent institution.(22) And already during that period began the work of artistic decoration of the towns by works of architecture, which we still admire and which loudly testify of the intellectual movement of the times. "The basilicae were then renewed in almost all the universe," Raoul Glaber wrote in his chronicle, and some of the finest monuments of medieval architecture date from that period: the wonderful old church of Bremen was built in the ninth century, Saint Marc of Venice was finished in 1071, and the beautiful dome of Pisa in 1063. In fact, the intellectual movement which has been described as the Twelfth Century Renaissance(23) and the Twelfth Century Rationalism--the precursor of the Reform(24) date from that period, when most cities were still simple agglomerations of small village communities enclosed by walls.