For all the Wikipedia haters
You gotta admit, this is a pretty cool visualization.
And what secondary source is going to publish something like that? Has published something like that? (Other than a few out-of-print wall-size timelines, mostly from the 18C and 19C.)
It could use a few tweaks – maybe tie it to small multiple maps, or perhaps scale the columns to land area somehow (although the names still need to be legible). But the title, coats of arms and links are nice.
And let’s not forget that Wikipedia allows you to quickly see historical figures’ basic life statistics, all the main titles and offices they held, as well as trace their predecessors and successors with a click of the link. Plus, you can check out the foreign language versions to find more details on certain (foreign) subjects.
You can still find the occasional factual error, and the interpretation in the text will only be as good as the sources the editors cite – but notice how they do use recent, even academic, sources.
Overall, props to Wikipedia I say. Not that I allow my students to cite it in their papers of course.