Sentence:  What really put primitive <WSD>ideals</WSD> in enveloping algebras of semisimple Lie algebras on the map was Duflo's fundamental theorem that any such <WSD>ideal</WSD> is the annihilator of a very special kind of simple module, namely a highest weight module. 
Meaning of the word marked with <WSD> tags:  A Lie subalgebra (subspace that is closed under the Lie bracket) 𝖍 of a given Lie algebra 𝖌 such that the Lie bracket [𝖌,𝖍] is a subset of 𝖍.