quis rex, quae curia, quale palatium,
quae pax, quae requies, quod illud gaudium,
huius participes exponant gloriam,
si quantum sentiunt, possint exprimere.
This is a part from a medieval chant. I am unsure if this is an exclamatory sentence.
In a dictionary, it is explained that "qui, quae, quod" as an interrogative adjective has an exclamatory meaning "what a....!". Likewise with "qualis, quale", "how....!". But with "quis, quid" there is no such explanation there.
Or, these "quis rex, quae curia,....." are the object clause of "exprimere" ? (I don't think this "exprimere" has anything to do with those, though.----"quantum sentiunt" is as it were the object of it.)