The document discusses models of urban development in pre-industrial Europe. It describes how cities grew due to increased trade following the Muslim invasions and Crusades. By the 15th century, some major European cities like London and Paris had populations of 80,000-120,000 people. However, by the 17th century most European cities had become overcrowded, unsanitary, and plagued by disease and crime. The document also outlines Gideon Sjoberg's stages of urban development and describes characteristics of pre-industrial primate cities.