Complex sentence: Engineer Giustino Cattaneo, Isotta Fraschini's technical director since 1905 and the driving force behind the company becoming a world-class car manufacturer resigned in 1933, six months later, in the summer of 1934, the last Isotta Fraschini Tipo 8B left the assembly line.
Split into simpler sentences: Engineer Giustino Cattaneo, Isotta Fraschini's technical director since 1905 and the driving force behind the company becoming a world-class car manufacturer, resigned in 1933. Six months later, in the summer of 1934, the last Isotta Fraschini Tipo 8B left the assembly line.