In 1530 the Reichstag of Augsburg demanded the holding of a council, in order to enforce the late edict, and for a due consideration of the monetary situation. Several attempts were made with this object, but fruitlessly, and the princes of the empire fell back on the only feasible but fatal plan of smaller Mint conventions between contiguous states. There is an endless series of these, and they render the history of German currency a perfect jungle of intricacies. Nine years later (1539), a monetary convention was summoned to meet at Augsburg by Ferdinand, heir to the empire. It proved fruitless. Again, in 1548, after the expiry of a similar period, the Reichstag at Augsburg declared for another monetary convention to relieve the disorder. The opinions of certain deputies to this convention, which met on the 8th October 1550, were as follows: "For fifty or even eighty years and more the ratio between gold and silver has been between 12 and 13. But in a gulden of those days there was an equivalence of more silver than in seventy-six of our kreutzers. Since then we apprise the Rhenish gold gulden and kreutzers less than foreign nations. Therefore France and England seek them."[12] A thorough inquest into the subject, or evaluation, was therefore ordered, and it was in accordance with the advice of the convention and with the report of the evaluation that the second imperial Mint edict was issued at Augsburg, 1551. This edict was drawn up on a ratio of 10.83 as a basis, and, as might be reasonably expected from the different ratios ruling abroad at the time, it proved as inoperative as its predecessor. The succeeding ten years witnessed a rise in the relative value of gold, or depreciation in that of silver, and the third and last of these imperial Mint edicts, that of the Emperor Ferdinand, issued at Augsburg, 19th August 1559, fixed a higher ratio, viz. 11.44. The Rhenish _gulden_ was raised from 72 to 75 kreutzers. The increasing production of silver indicated by this change is still more clearly marked in the resumption of the coining of the imperial thalers, at the instigation of the Reichstag at Augsburg, 30th May 1566. The advice of this Reichstag was the outcome of the monetary convention held at Nördlingen two years earlier, at which strong complaints were appointed to be made before the Reichstag of the weak state of the coin, and of its under-valuation.