Throughout the seventeenth century the haciendas grew in significance. They held much of the land and water resources, expanded their labor force, intensified their control over the market, and consolidated their territorial rights in accordance with _composiciones de tierras_. (The phrase _composiciones de tierras_ belongs to the legal terminology of the time. It relates to a legal mechanism that was instituted by the Spanish Crown during the first half of the sixteenth century but which was applied mainly during the seventeenth century. It made it possible to legalize properties whose titles were not in order.) They sought to make improvements by constructing, for example, buildings, irrigation systems, roads, granaries, and shelters for livestock. Together, these made it possible to increase agricultural yields substantially. It was not an easy process, often involving transfers of hacienda property, severe indebtedness of their owners, and great difficulties in production. Hacienda expansion proceeded throughout the following two centuries. Huge tracts of uncultivated land were transformed into farmland and impressive water distribution systems opened up new areas to irrigation. The population, constantly growing, demanded an ever greater quantity of food. Much land that had been devoted to the raising of livestock was turned over to cultivation, and the stock were gradually displaced until livestock haciendas came to be located mainly in the north of the country. However, this was not a period of unimpeded progress: there were severe periods of crisis, sharp fluctuations in production, a lack of continuity in the transmission of property, and frequent bankruptcies. Hacienda properties tended to be deeply mortgaged to ecclesiastical institutions and to individual lenders. [Illustration: Hacienda Uxmal, Yucatán: main gate.] When dictator Porfirio Díaz assumed power in 1877, a boom period for the hacienda began. Historical circumstances were favorable, and the government offered all manner of facilities to the livestock and farm impresarios. The substantial increase in the country's population, as well as the strengthening international economy, created a great demand for farm and livestock products. The consumption of goods from the tropics, such as coffee, cacao, sugar, tobacco, and vanilla, grew considerably during this time both in Europe and in the United States. The same thing happened with certain basic materials, among them _henequén_, rubber, chicle, and _ixtle_. (_Ixtle_ or _istle_ is the name given to the hard fibers that are extracted from different plants of the genus agave, of which the most important are the _maguey_ and the _lechuguilla_. They are raised mainly in northern Mexico.)