Frederick Augustus was, like his father, of feeble constitution, and moreover, as he himself complained later on in life, had been at once spoiled and neglected in his youth; and he was unable through weakness to ascend a height. He did not walk or ride, but went about in a carriage. The January (1769) after he came to the Electoral crown, he married Amelia Augusta of Zweibrücken, sister of Max Joseph, afterwards first King of Bavaria. She was only seventeen at the time.

The favourite son of his mother was Charles. This prince had been hearty and in full possession of his limbs in his early age, but when he reached the years of eleven or twelve, he became crippled and doubled up like his father. Wraxal says that beside him Scarron would have passed as a beauty. He was so feeble and paralysed that he could only be moved about on a wheeled chair. He died in 1781. His elder brother, the Elector, though not a vigorous man, was not a cripple.

One of the attendant gentry on the Electress Mother, in Rome, was the Marquis Aloysius Peter d'Agdolo, son of the Saxon Consul in Venice, Colonel of the Lifeguard, and Adjutant General to Prince Xavier whilst he was Administrator.

Agdolo advised the Electress Mother to raise money to meet her difficulties by selling to her son, the Elector, her claims on the Bavarian inheritance. Her brother, Maximilian Joseph, was without children; and the nearest male claimant to the Electoral Crown of Bavaria was the Count Palatine of Sulzbach, only remotely connected. It was, therefore, quite possible that Bavaria might fall to a sister. Now on the death of her brother, the Dowager Electress of Saxony certainly intended to advance her claims against any remote kinsman hailing through a common ancestor two centuries ago. But whether she would be able to enforce her claim was another matter. She might sell it to her son, who would have the means of advancing his claim by force of arms and gold. This was in 1776. Maria Antonia was delighted with the scheme and at once hastened to Munich to put it in execution, taking with her all her diamonds which she had managed to redeem from pawn.

Whilst she was on her way to Munich, Agdolo was despatched to Dresden, to open the negociation with her son, not only for the transference of her rights on Bavaria, but also for the pawning of her diamonds, to her son.

She had urgent need of money, and in her extremity she conceived an audacious scheme to enable her at the same time to get hold of the money, and to retain her rights on Bavaria. The plan was this:—As soon as she had got the full payment from the Elector for the resignation of her claims in his favour, she had resolved suddenly to proclaim to the world that he was no son at all of the late Elector Frederick Christian—that he was a bastard, smuggled into the palace and passed off as the son of the Elector, much as, according to Whig gossip, James the Pretender was smuggled into the palace of James II. in a warming pan, and passed off as of blood royal, when he was of base origin.

Frederick Augustus thus declared to be no son of the House of Saxony, the Electoral crown would come to her favourite son Charles, who was a cripple. The Elector was not deformed—evidence against his origin; Charles was doubled up and distorted—he was certainly the true son of the late Elector, and the legitimate successor.

If Maria Antonia should succeed—she would rule Saxony in the name, and over the head of her unfortunate son Charles, and her rights on Bavaria would not have been lost or made away with.

Arrived in Munich, she confided the whole plan to her ladies-in-waiting. She told them her hopes, her confidence in Agdolo, who was gone to Dresden to negociate the sale, and who was thoroughly aware of her intentions.