Before then? It stood for general democratic desire and the idea that people should have the power over government rather than the old establishments. And before that… the concept of left and right didn’t exist. Since they came up during the French Revolution when the revolutionary members sat on the left side of the assembly in Versailles, opposite the supporters of the old regime on the right side.
Like… are you talking about ideological drift? In that case, all political forces have moved towards the right since the 80s. Most prominent in the US, where our “left” party is actually center right