The world lost one of its leading conductors and a great patron of Czech classical music on Wednesday with the passing of Sir Charles Mackerras, who has died of cancer at the age of 84. In a long career of many highlights, Sir Charles became a notable specialist on the Czech composer Leoš Janáček and played a major role in championing the work of other Czech classical masters, like Bohuslav Martinů and Antonín Dvořák.