Sweet smelling plant materials have attracted human attention since ancienttimes. It was realised that some plant materials have a better aroma whenplaced on burning firewood, which is how rituals all over the world came toinclude both plants and incense. The ceremonial feeding of the perpetualfire in Zoroastrian fire temples, performed five times in 24 hours, iscalled būy (aroma). The ancient Iranian scriptures – theAvesta and scriptures written in Pahlavi – all mention aromatics and severalkinds of incense.