The travelling party of Maës Titianus penetrated farthest east along the Silk Road from the Mediterranean world, probably with the aim of regularising contacts and reducing the role of middlemen, during one of the lulls in Rome's intermittent wars with Parthia, which repeatedly obstructed movement along the Silk Road. Intercontinental trade and communication became regular, organised, and protected by the "Great Powers". Intense trade with the Roman Empire soon followed, confirmed by the Roman craze for Chinese silk (supplied through the Parthians), even though the Romans thought silk was obtained from trees. This belief was affirmed by Seneca the Younger in his Phaedra and by Virgil in his Georgics. Notably, Pliny the Elder knew better. Speaking of the "bombyx" or silk moth, he wrote in his Natural Histories "They weave webs, like spiders, that become a luxurious clothing material for women, called silk." The Romans traded spices, glassware, perfumes, and silk.