Definition of "congenial"

No sluggish tide congenial to the glooms; / This, as it frothed by, might have been a bath / For the fiend's glowing hoof - to see the wrath / Of its black eddy bespate with flakes and spumes.

1855, Robert Browning, Childe Roland to the Dark Tower Came, section XIX

What was it that made this notion of mimesis, in spite of its inherent difficulties that only the dialectical method enables him to avoid, seem so useful and congenial to Plato?

1961, J. A. Philip, “Mimesis in the Sophistês of Plato”, in Proceedings and Transactions of the American Philological Association 92, pages 453–468