Complex sentence: Ancient Greek was widely known to scholars, but the details of its use in the Hellenistic period as a government language in Ptolemaic Egypt were not familiar: large-scale discoveries of Greek papyri were a long way in the future.
Split into simpler sentences: Ancient Greek was widely known to scholars, but they were not familiar with details of its use in the Hellenistic period as a government language in Ptolemaic Egypt. Large-scale discoveries of Greek papyri were a long way in the future.