Should the "600 ducats" part of the Rudolf story be dismissed for good?

[bi3mw]

So would you consider this enough evidence to assume that "600 ducats" was probably an incorrect price?

Yes, that seems to me to be sufficient evidence. One must also consider that the VMS has no particularly "valuable" illustrations and the text is not readable. So, even in Rudolf's time, it was rather a cusiosity which might not have driven the price up. Rudolf was known for his preference for curious things (not only books) but he was also very broad in his acquisitions. He will hardly have spent an enormous sum on a single "book-artifact". As far as I know, he was chronically short of cash anyway. So he couldn't spend the money as he pleased.

His father left him the monetary system in deep disarray, and this grew through the lack of order, through Rudolf's excessive expenditures on the arts and sciences, on their representatives and his collections, and on his minions, but above all through the costs caused by the defense of the frontiers and later by the war against the Turks. From the beginning, the regular income was barely enough to pay the interest on the debts. R. was therefore dependent on the extraordinary taxes of the house countries and the empire.