While the earlier universities gradually arose as the result of a long local evolution, it in time became common for others to be founded by a migration of professors from an older university to some cathedral city having a developing _studium_. In the days when a university consisted chiefly of master and students, when lectures could be held in any kind of a building or collection of buildings, and when there were no libraries, laboratories, campus, or other university property to tie down an institution, it was easy to migrate. Thus, in 1209, the school at Cambridge was created a university by a secession of masters from Oxford, much as bees swarm from a hive. Sienna, Padua, Reggio, Vicenza, Arezzo resulted from "swarmings" from Bologna; and Vercelli from Vicenza. In 1228, after a student riot at Paris which provoked reprisals from the city, many of the masters and students went to the studium towns of Angers, Orleans, and Rheims, and universities were established at the first two. Migrations from Prague helped establish many of the German universities. In this way the university organization was spread over Europe. In 1200 there were but six _studia generalia_ which can be considered as having evolved into universities--Salerno, Bologna, and Reggio, in Italy; Paris and Montpellier, in France; and Oxford, in England. By 1300 eight more had evolved in Italy, three more in France, Cambridge in England, and five in Spain and Portugal. By 1400 twenty-two additional universities had developed, five of which were in German lands, and by 1500 thirty-five more had been founded, making a total of eighty. By 1600 the total had been raised to one hundred and eight (R. 100, for list by countries, dates, and method of founding). Some of these (approximately thirty) afterwards died, while in the following centuries additional ones were created. [10]