Who is Marcos de Niza from A Short Account of the Destruction of the Indies and what is their importance?

Brother Marcos de Niza was a Franciscan Friar. He wrote a letter to bishop of Mexico and later to the local authorities back in Spain about the horrible conditions in Peru, and the atrocities that the Spaniards there were committing with no legal right. He experienced everything first-hand and was on the side of the natives because they were so generous and always treated the Europeans with kindness and generosity. He told the Spanish authorities that Pizzarro had unjustly killed Atahualpa and other leaders of the Peruvian provinces. His reason for writing the letter was to get the King to take action in order to stop all of the atrocities and to be able to have good relations with the people of the region. The Spaniards were doing much harm to the Spanish crown and he wanted it to stop.