Readers of Poul Anderson's History of Technic Civilization will know what I am getting at here but it may be helpful to explain further to any reader of this blog who is less familiar with the Technic History. The post, "Stepping Stones And Patterns" (see the above link), lists many fictitious events. Most of these events occur in only a single work. That alone would have been more than enough to generate a long and impressive series. However, three of the listed items:
van Rijn as a Master Merchant;
...Falkayn and Adzel working in a team for van Rijn...;
...the Roidhunate as a threat to the Terran Empire in Flandry's time -
- each represents a significant series in its own right. Thus, the History comprises:
the van Rijn series;
the trader team series;
the Flandry series;
several other works that bind the History together, some set before van Rijn, between van Rijn and Flandry or after Flandry but others contemporary with one of these central figures.
Thus, the entire effect is indeed that of a many-sided history and not of a single linear sequence.