Post WWII. They took the reconstruction money and used it to create wealth from not only rebuilding their own country, but for all of lazy ass Europe too.
The Germans have arguably seen times much harder than any of us, our parents, or our grandparents have known following WWI and WWII especially then, later, having to basically bail-out the former E. German nation. I think that has inculcated something in their psyche which makes them different from the other lazy-asses in the EuroZone.