Las Siete Leyes (Spanish: [las ˈsjete ˈleʝes], or Seven Laws were a series of constitutional changes that fundamentally altered the organizational structure of Mexico, ending the first federal period and creating a unitary republic, the Central Republic. Formalized under President Antonio López de Santa Anna on 15 December 1835, they were enacted in 1836. They were intended to centralize and strengthen the national government. The aim of the previous constitution was to create a political system that would emulate the success of the United States, but after a decade of political turmoil, economic stagnation, and threats and actual foreign invasion, conservatives concluded that a better path for Mexico was centralized power. The Siete Leyes were revised in 1843, making them more workable, b