Túpac Inca's son Huayna Cápac added a small portion of land to the north in modern-day Ecuador. At its height, the Inca Empire included Peru, western and south central Bolivia, southwest Ecuador and a large portion of what is today Chile, north of the Maule River. Traditional historiography claims the advance south halted after the Battle of the Maule where they met determined resistance from the Mapuche. This view is challenged by historian Osvaldo Silva who argues instead that it was the social and political framework of the Mapuche that posed the main difficulty in imposing imperial rule. Silva does accept that the battle of the Maule was a stalemate, but argues the Incas lacked incentives for conquest they had had when fighting more complex societies such as the Chimú Empire. Silva also disputes the date given by traditional historiography for the battle: the late 15th century during the reign of Topa Inca Yupanqui (1471–93). Instead, he places it in 1532 during the Inca Civil War. Nevertheless, Silva agrees on the claim that the bulk of the Incan conquests were made during the late 15th century. At the time of the Incan Civil War an Inca army was, according to Diego de Rosales, subduing a revolt among the Diaguitas of Copiapó and Coquimbo.