Complex sentence: While in port, La Pérouse received orders to proceed as quickly as possible to Australia to investigate a rumored British settlement at Botany Bay but before leaving, he needed to get reports of the voyage so far back to Paris.
Split into simpler sentences: While in port, La Pérouse received orders to proceed as quickly as possible to Australia to investigate a rumored British settlement at Botany Bay. Before leaving, however, he needed to get reports of the voyage back to Paris.