Frankincense and myrrh reached the ancient Mediterranean and the Near East only because an entire commercial and political system existed to move them there, and the offering that later ages took for granted rested on a supply chain most worshippers never saw. Both resins are tapped from trees, Boswellia and Commiphora species, that grow almost exclusively in southern Arabia and the Horn of Africa, regions with no other product of comparable value to export in antiquity, and camel caravans carried the dried resin north along what became known as the Incense Route, through way stations in what is now Yemen, Oman and the Nabataean kingdom centred on Petra, a city whose wealth and elaborate rock-cut architecture were built substantially on taxing and provisioning this single trade.
Roman writers, Pliny the Elder among them, recorded the resin's price as comparable to precious metal by the time it reached the Mediterranean, inflated by distance, taxation at each kingdom it passed through, and the deliberate secrecy southern Arabian traders maintained about where exactly the trees grew, since that ignorance protected their monopoly. The gospel account of the magi bringing frankincense and myrrh to the infant Christ trades directly on that established value, offering substances any contemporary reader would have recognised as costly imports from the edge of the known world rather than as an arbitrary poetic choice, and the same commercial network that carried them north is what made incense offering, rather than remaining a regional Arabian practice, into a fixture of temple worship across the entire ancient Mediterranean world.