Amalia was a wilful young woman married to a boy, and saw her chance to boss him around. Du Tillot was installed by Louis XV to do the actual ruling for the young boy. The arrival of a beautiful, proud Austrian Archduchess, who was pissed at the arrangement was not doing to respect a royal favourite who was not born royal. She went her own way and refused to be rule by him.
Thank you for this, Eric_Lowe! I figured it out on my own and thanks for this confirmation.... Amalia did not want to take orders from a non-royal. I understand that Amalia (and Ferdinand) could've behaved differently but I also understand their wanting to be independent. The earlier explaination of CountessKate on Parma's sovereignty made a lot of sense to me.
I just found out some other information on the situation in 1771-1773 (from the letters of Maria Theresia to Count Mercy de Argenteau in France):
June 1771- The Empress wrote to Mercy: " The Infanta, my daughter, has written to me of her fresh attempts against du Tillot, but I have answered her that I remember quite well the promise she and her husband gave to the two great Kings, that they would let du Tillot act for four years without interference, and that she ought to respect me more than to speak to me of such a thing. ... I fear that the disorders of Parma are such that they no longer admit of remedy; I believe that France and Spain recognise this, and wish to draw me into the turmoil. I can tell you that I do not want to associate myself with it, for many reasons; you must, therefore, drop any such proposal, for it can never be. They have another idea, as bad as the first, to send the Infant traveling and return me my daughter. I declare that I will never stand that; the young people must remain together. It would be shameful for the Bourbons to desert thus a Prince of their house. I should be very sorry to have to give a plump refusal to my daughter's return; either she must come with her husband (which would be the more natural arrangement), or she stays in Parma or Piacenza. . . . They are all right together just at present: let them remain so. Rather than have them in my house, I can tell you, I would rather they went to Venice."
1771: "As for the Parma affairs, I shall give them up, as I am convinced of the utter uselessness of all my efforts to recall my daughter, the Infanta, to her duty. If I had you ( Mercy) at Parma, there would be some grounds for hope, but as things are there is nothing to do...."
June/July 1773 from Maria Theresia: “The Infants of Parma still continue their gait; nevertheless I admit that they ought to be reinstated in their pensions [Marie Amelie had been reduced to selling and pawning her diamonds] . . . and the arrears made up..."
November 1773: “There are three grandchildren already this year, and a fourth I expect in December. God be praised! . . . I hear my daughter in Parma is moving heaven and earth to come here. The ministers of Spain and France wish it in order to be able to settle the country, and make the Infant travel in France and Spain. This does not suit me at all, and if she cannot follow her husband she will have to stay behind with her children in Parma. That is her place, and we are going to give a flat refusal to her request. ... I am sorry for her with that fool for a husband but I cannot approve of these trips here: it would only increase my troubles of which I have enough...”
MARIE ANTOINETTE'S letter to her mother is the first of the correspondence with which commences the new year. She has just learned that both her sisters, the Infanta of Parma and the Queen of Naples, are awaiting the birth of children. " When shall I be able to say the 13 January 1773 like?” The Infant of Parma, still in 1773 deepest disgrace, had written the important news to the King, the Dauphin, and his brothers ; but the King had not permitted any one to reply, and Marie Antoinette followed the example of both her families. "It is to be hoped, that when the Infanta sees herself with many children about her, she will learn her duty and try to please her relatives. . . .”
I can't say I agree with the punishment for the two (as declared by Louis XV and Charles III)......and that my sympathies are Amalia and Ferdinand, not with France and Spain. All this trouble for a small, insignificant and not quite wealthy duchy? IMHO, Louis XV and Charles III just wanted to assert their power.