Why is purple used for Law in academic dress?

Answer 1

I don't actually think any of the academic colors have any meaning, they are just traditional. However, if I had to assign a meaning, I would say that purple has always been the color of royalty, and those in the legal system were working in support of the king's law.

Answer 2

purple is the color associated with royalty and government as the roman forum of senators wore purple robes to set themselves apart from ordinary citizens . It's probably a reflection of those times .