Where did the concept of multiple parallel plotlines (that may or may not interact and converge) originate? These days they're also known as throughlines, subplots, narrative/character arcs, series.
I know it is quite an intuitive thing, but I would really like to know the first recorded instance of someone talking about it/teaching the tabular method (each row/column is an arc and each column/row is a point in time-> usually divided into Acts or chapters). In fact, I can't find any book at all that discusses this tabular method.