The French modeled their colonial system on their predecessors, the Ottomans, by co-opting local tribes. In 1843 the colonists began supervising through "bureaux arabes" operated by military officials with authority over particular domains. This system lasted until the 1880s and the rise of the French Third Republic, when colonisation intensified. Large-scale regrouping of lands began when land-speculation companies took advantage of government policy that allowed massive sale of native property. By the 20th century Europeans held 1,700,000 hectares; by 1940,  2,700,000 hectares, about 35 to 40  percent; and by 1962 it was 2,726,700 hectares representing 27 percent of the arable land of Algeria. Settlers came from all over the western Mediterranean region, particularly Italy, France, Spain and Malta.