Yes, "corte" certainly derives from absolute monarchies and the expression "to hold court" derived therof. However, trying to use logic to conclude that, since the verbal expression is in common use, so would be the related noun "court" is a slippery slope indeed (many a translation attempt has been derailed by such daring maneuvers). The word we need here is "retinue".(*)

Next, a good equivalent for "bajular" in this context is to fawn. However, we again need to refrain from the siren song of Logic (mind you, that is coming from a mathematician) and avoid the tempation to force the word "fawner". Just as a kind of "menção honrosa", if I may, the verb "to flatter" is close but not as derogatory as "bajular" in this specific context. Hence "flatterer", which is a common enough word ,turns out not to be such a good fit. On the other hand, when taken out of context, a "sycophant" is not exactly a "bajulador", but it happens to work quite well in this case.

Finally, in spite of the the definite article used in "..veio da corte de bajuladores, nacionais e estrangeiros, que acreditam...", I believe the indefinite article will flow better in English: "...came from a retinue of sycophants, domestic as well as foreign, which think...". And yes, I did consider the alternative "retinue of domestic and foreign sycophants" but concluded that it would be better not to wedge that qualifier between "retinue" and "sycophants"

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(*) Just for fun, it occurs to me that, were the contex American and juvenile, the word "posse" would fit. Once again, it's all about the context.