Poisoned blades are common in history. The usual mixture was from snakes. India and Persia are very much used to such and commonly you find poison on spears and arrows.
In fact the Greek word for Bow was Toxon ! Another fatal substance deadly nightshade was called Strychnos... mainly the poison for spears.
Please see
https://books.google.com.om/books?id...blades&f=false
In fact the Persian punishment for poisoning someone ...more formally with say a poisoned cup... was to take the offender and place their heads on a large flat stone and then to take another stone and pound their heads to pulp.
