Vittorio tells Sydney and Nigel that Count Raphael Onofore has a big Ides party on the 15th of every month. The warning, "Beware the Ides of March" comes from the fact that Julius Caesar was murdered by a group of Roman senators on the Ides of March (the 15th), 44 BC. It was popularized by Shakespeare's use of the warning in his play 'The Tragedy of Julius Caesar'. Most people (apparently including the Count) believe the Ides of each month falls on the 15th, which is incorrect. The Ides is the 15th day of "full months" and the 13th day of hollow ones, one day earlier than the middle of each month. In March, May, July, August and October it was the 15th day of the month; in other months it was the 13th.
When the alchemist puts on the impenetrable golden armor, it bends like plastic under his hand.