Read the excerpt from Utopia. But after the ambassadors had stayed a day among them, and saw so vast a quantity of gold in their houses (which was as much despised by them as it was esteemed in other nations), and beheld more gold and silver in the chains and fetters of one slave than all their ornaments amounted to, their plumes fell, and they were ashamed of all that glory for which they had formed valued themselves, and accordingly laid it aside . . .

This detail supports the central idea that riches are not important to Utopians, and uses an account of an event to make a larger point. It is best described as a(n)

fact.
analogy.
anecdote.
example.