<P> Since 1960 several Hispanists and anthropologists, like Julian Juderias or Cook y Borah have challenged both the numbers and the causes offered by Raphael Lemkin . Recent genetic studies Their genetic testing of the present - day American native population showed that a 96% decline did not occur, based on the remaining genetic diversity of the native populace tested . Their study allowed for a maximum possible decline of 25% in the population based on their findings . Brendan D. O'Fallona and Lars Fehren - Schmitz separately estimated a historic native mortality of about 50% loss with a quick recovery and little loss in diversity . Quentin D Atkinson Cook and Borah Universidad de California en Berkeley conducted a decade long study on the historical native demographics of Mexico and estimated that the overall decrease in native population was only 3% . Rosenblat estimates a lower number for Mexico and Colombia . Acuna - Soto R1, Romero LC, and Maguire JH suggested the rate of mortality from disease in native American populations at around 45% . </P> <P> Regardless of the specific number, it is widely agreed that the peak in mortality started in 1545 and peaked some years later after the New Laws were put in place, the encomienda system was abolished, and women, and more importantly children, were allowed to migrate . What mortality of the native population did occur was mainly attributable to disease . Most scholars agree that the main culprits were European infantile diseases like smallpox, measles, and chicken pox . Elsa Malvido suggests that the plague caused the hemorrhagic fevers described by the Spanish physicians, while a recent, controversial study recently proposed by microbiologist Rodolfo Acuna - Soto suggests that the diseases that decimated the population were actually a native hemorrhagic plague carried by rats . </P> <P> The encomienda system was the subject of controversy in Spain and its territories almost from its start . In 1510, an Hispaniola encomendero named Valenzuela murdered a group of Native American leaders who had agreed to meet for peace talks in full confidence . The Taíno Cacique Enriquillo rebelled against the Spaniards between 1519 and 1533 . In 1538, Emperor Charles V, realizing the seriousness of the Taíno revolt, changed the laws governing the treatment of Indians laboring in the encomiendas . Conceding to Las Casas's viewpoint, the peace treaty between the Taínos and the audiencia was eventually disrupted in four to five years . The crown also made two failed attempts to end the abuses of the encomienda system, through the Law of Burgos (1512--13) and the New Law of the Indies (1542). Furthermore, these laws were indeed beneficial to the authorities . </P> <P> The priest of Hispaniola and former encomendero Bartolomé de las Casas underwent a profound conversion after seeing the abuse of the native people . He dedicated his life to writing and lobbying to abolish the encomienda system, which he thought systematically enslaved the native people of the New World . Las Casas participated in an important debate, where he pushed for the enactment of the New Laws and an end to the encomienda system . The Laws of Burgos and the New Laws of the Indies failed in the face of colonial opposition and, in fact, the New Laws were postponed in the Viceroyalty of Peru . When Blasco Núñez Vela, the first viceroy of Peru, tried to enforce the New Laws, which provided for the gradual abolition of the encomienda, many of the encomenderos were unwilling to comply with them and revolted against him . </P>

Why did the spanish abolish the encomienda system