Human Rights Coursework

really stuck on coursework question concerning Article 7 ECHR (No punishment without law) based on someone being charged under law that dates back to the 16th century???

its a problem question which says she is charged under a law which dates back to the 16th century and was last used in the 1920s. So i need to talk about how that breaches her rights under Article 7 ECHR which states there can be no punishment without law.

All the information i can find talks about how new law can apply retrospectively and nothing about how old law can/ cant apply to modern day situations which is what i need