Original: His son Ernest Augustus II , who succeeded him in 1748 , died in 1758 , whereafter Empress Maria Theresa appointed his young widow , Duchess Anna Amalia , regent of the country and guardian of her infant son , Charles Augustus .
Simplified: Ernest Augustus II , who succeeded in 1748 , died in 1758 , and his young widow , Anna Amalia , became regent for her infant son , Charles Augustus .