Complex sentence: For introducing the Persian garden, Pompey and Tubero mockingly nicknamed Lucullus "Xerxes togatus" (Xerxes in a toga, ie a Roman Xerxes), demonstrating that it was well understood in Rome that this new luxury of gardening originated in Persia.
Split into simpler sentences: For introducing the Persian garden, Pompey mockingly nicknamed Lucullus'the Roman Xerxes', and Tubero called him'Xerxes in a toga'. These comments demonstrate that it was well understood in Rome that this new luxury of gardening originated in Persia.