Why did the treasure fleets stop?

From East Asia·An enduring case

Zheng He's fifteenth-century fleets dwarfed anything Europe would float for centuries, then the voyages ceased and records were neglected or destroyed. Historians explain the halt through court factionalism, fiscal strain, steppe threats or Confucian priorities, each account selecting different evidence as decisive. The event is fixed; the explanation is still under construction.

The concepts this raises

Each of these gives a class a different way into the same case.

EvidenceGrounds of Knowledge
What is offered in support of a claim. Evidence is not the same as proof: it raises or lowers how likely a claim is, and its force depends on how it was gathered, what it was gathered for, and what else it is consistent with. Asking what would count as evidence against a claim is usually more revealing than listing evidence for it.
ExplanationGrounds of Knowledge
An account of why something is the case rather than merely that it is. Explanations are judged by more than accuracy: scope, simplicity, fruitfulness and the ability to say what would have happened otherwise all matter, and these criteria can pull against one another.

Where it sits in the knowledge framework

Methods and tools
The practices, conventions, instruments and forms of reasoning through which knowledge here is actually made, together with the assumptions those methods build in and what they are structurally unable to detect.

Areas of knowledge

Cases that raise a concept this one raises, but in a different area of knowledge or a different part of the world. That contrast is the point: it is what shows a student the concept travels.