Incense used at ancient China's largest Buddhist temple, the Famen Royal Temple, has been determined to be composed of mixtures of Elemi resin, agarwood, and frankincense. All are native to regions thousands of kilometers away, and the find confirms the importance of incense to the creation of trade routes to and from China.

Society without modern sewage systems and reliant on the labor of animals not known for their toilet training prized pleasant but powerful smells. Being so valuable for its weight, incense became a prime product for trading over long distances. Indeed the famous Silk Road between China and the Middle East could as easily have been called the Incense Road. By bringing civilizations into contact, trade routes allowed the spread of something even more valuable – ideas – and in the process created the modern world.

While the importance of incense is recorded in historical documents, the exact nature of the scents has remained a mystery. Now the chemical composition of incense from arguably China's most important Buddhist Temple has been reconstructed and described in Proceedings of the National Academy of Sciences. The announcement follows the recent replication of the perfume Cleopatra used to charm Roman emperors; scent archaeology's time has apparently come.

Historical records indicate incense was widely used in China from at least 2,200 years ago. For much of that time local species ingredients were used, which according to the paper were primarily fragrant thoroughwort, lily magnolia, and mugwort. By the time of the Western and Eastern Han dynasties (202 BCE-220 CE) books and medical prescriptions started to refer to incense imported from Arabia, India, and possibly Africa. We can make a reasonable guess at what these were, but samples for precise analysis have been hard to find, making the discoveries in the forecourt of the Famen Temple significant.

The temple is located near Xi'ian, central China, at a key stopping point on the overland trade routes between China and Arabia. It's unclear when the temple was first built, possibly dating back to 386–534 CE, and it housed what were claimed to be four of Buddha's fingerbones. Three of the bones have been shown to be fake (two of them were stone), Despite the vast majority of original relics across many religions being highly dubious, Chinese authorities continue to maintain the fourth finger really is Buddha's. The temple was held in high regard by China's rulers of the era, making it rich enough to afford large quantities of the finest incense.

The temple was renovated during the Ming Dynasty, but when a pagoda established in the renovation collapsed in 1981, it inspired archaeological explorations that exposed more ancient spaces.

Along with the purported fingerbones, the archaeologists found containers filled with aromatic substances and thought to date to 499-532 CE, three of which they subjected to mass spectrometry, Fourier-transform infrared spectroscopy, and pyrolysis.

Two of the samples combined Elemi resin with agarwood, while the other was a combination of agarwood and frankincense. This makes the scents the oldest evidence of Hexiang, the blending of different incenses. All three materials must have undergone immense journeys to reach the temple, coming from locations almost as distant from each other as from their destination.

Frankincense came from southern Arabia and the horn of Africa, likely along the Silk Road, agarwood is native to India and South-east Asia and was probably imported by sea. Elemi today is mainly sourced from Africa, but some species of the Burseraceae and Canarium trees that produce it are found in southern China and the Philippines. However, the authors were unable to confirm the variety of Elemi, and therefore its origins.