Is Inequality Really Causing Growth?

Growth could be that question we've decided to ignore at the beginning, and that the growth is causing the inequality. And also whether inequality really does cause growth or not. For instan if you say, compared countries across the world, yu wat, you see, typically medincome countries have high inequality. They were rich in the past, but nowadays, in relative terms at least, they have tipily fallen save compared it to ancient countries,. Now is it inequality that causes that? Or is it something different? Because that's difficult and to say simply by looking only at this cross country comparison.