Complex sentence: In most countries, the protocol of the head of state comes before all others, however in the EU the Parliament is listed as the first institution, and hence the protocol of its President comes before any other European, or national, protocol.
Split into simpler sentences: In most countries, the protocol of the head of state comes before all others. However, in the EU the Parliament is listed as the first institution, and hence the protocol of its president comes before any other European, or national, protocol.