Complex sentence: Historically the poisoning was associated with the "Rhododendron ponticum" found around the Black Sea, according to Pliny and later Strabo the locals used the honey against the armies of Xenophon in 401 BCE and later against Pompey in 69 BCE.
Split into simpler sentences: Historically the poisoning was associated with the "Rhododendron ponticum" found around the Black Sea. According to Pliny and later Strabo the locals used the honey against the armies of Xenophon in 401 BCE and later against Pompey in 69 BCE.