Anyone who truly wants to understand their family must stop merely collecting names and dates. That it took humanity four hundred years to arrive at this idea is, in itself, rather a family pattern.

When the Austrian historian and diplomat Michaël Eytzinger published his work Thesaurus Principum in Cologne in 1590, he incidentally invented a numbering system for ancestors that is still used today: the "Ahnentafel". His goal was as sober as the diplomacy of his age: to systematically record the family trees of Europe's ruling houses – for inheritance matters, marriage negotiations, and political alliances. Who was related to whom decided war and peace. What these relatives felt for one another was of no interest to anyone.

For centuries, family trees remained a tool of life's bookkeepers. Parish registers, kept systematically from the 16th century onward, supplied the data. Who married whom? Who died when? Who inherited what? These were important questions, no doubt. But the one question that would change everything was missing: Why do families do what they do – and why can't they stop?

It would take until the 20th century for someone to have the idea that family diagrams might also serve what stands between the lines of the parish registers – relationship patterns, emotional bonds, and those recurring conflicts that every family knows but none wishes to admit.

The journey from the family tree to the therapeutic soul map is a story that begins with a baker who fled the Habsburgs, and concludes for now with a screen on which you can make family patterns visible with a single click. In between: a psychiatrist who put his own family on the couch, a Russian-studies student who revolutionized therapy, and a tragically early-departed visionary who already believed in digital genograms back in the eighties.

But one step at a time. Let us begin with the psychiatrist who refused to make an exception of himself.