How to Unlock Assassin's Creed Unity Medieval Armor [PS4 - Xbox One - PC]
I finally found you.
Guide Trophy / Objective "From the past"
In order to unlock themedieval armor in Assassin's Creed Unity you need to complete 3 puzzles in the armor room, in the Café Théâtre. To complete these puzzles you need the fragments which are obtained by completing the secondary missions related to Riddles of Nostradamus. Then solve the puzzles by following the guide to complete the Nostradamus Enigmas and then use the fragments to unlock the medieval armor.
When you have unlocked it, you will be able to wear the armor from the character customization menu, you will find it under the name of "Costume of the Master Assassin Thomas de Carneillon".
Consult the Assassin's Creed Unity cheats and guides tab for other useful guides on this game, while below you can see a video showing the use of the fragments in the cafe, but remember that first you will have to recover them (use the guide linked above to find them all ).