Francis IV met Louis-Philippe and Lafitte at Marseille in March 1831. His professions of agreement with Menotti had endeared him to Liberals, despite his dubious reputation. From over the border in the Kingdom of Sardinia, news came that King Charles Felix was ailing, and that Charles Albert, more sympathetic to the cause, would soon be on the throne.
Charles Albert - at this stage of his life - is not at all a liberal. He was in his youth, and as a regent for Charles Felix granted a Constitution patterned on the Spanish one of 1823. Then he was forced to recant, the constitution was abolished and he took a turn toward despotism. One of his first acts in assuming the throne was to persecute the Carbonari. I grant that when he took the throne the liberals expected him to grant again a constitution, but they were sadly disappointed. On the other hand, he was a reformist king, and gave a strong impulse to industrialization of Piedmont (compare with Francis IV, who preferred agriculture to industry, since peasants were more reliable than industry workers
). This is still in the future at this stage; so maybe you are not completely wrong: you just give voice to the expectations of the Italian liberals.
Louis-Philippe agreed that Menotti , on behalf of Francis IV, could stir up and annex Parma without French intervention- he had little love for Marie-Louise, its duchess. However, he was warned off trying to annex Lucca, and against fomenting trouble in Tuscany for now.
Francis IV returned to Mantua, where he was based. He allowed Menotti to head off to Parma, and raised his army. On the 6th May, without warning, he entered Parma's territory before dawn. On this signal, Carbonari rose up and seized key buildings in the major towns. Marie-Louise herself was swiftly deposed. Within 3 weeks, the Grand Duchy of Modena and Parma had been declared, recognised by France. Austria was perplexed. Two of its ostensible clients had gone to war- it didn't seem to matter in general. Francis I of Austria couldn't work out how to intervene.
I would say that he returned to Modena. Mantua is one of the 4 main fortresses in Austrian Italian possessions.
Marie-Louise was the daughter of Francis I, and at the Vienna Congress a lot of efforts had been devoted to find a proper throne for her. Admittedly, Marie-Louise was not exactly loved in Vienna (she was considered politically dangerous), and Francis IV was also an Austrian client. Still, I'd think unlikely that the Austrians would accept a fait accompli so easily.
The other question that begs an answer is: will a constitution be granted? IMHO, if Francis IV dithers (or worse refuses to grant a constitution), the carbonari will be disillused very soon, and turn against him: which will mean an insurrection and an open door for Austrians to come in. If he grants a constitution (I'd assume patterned on the new French one), he'll become anathema for all the representatives of the old order. Francis is riding a tiger, and cannot get off.
But Francis IV had not yet had enough. Still professing his newly-found enthusiasm for Italian liberation, he declared himself its greatest hope, which irritated the Sardinians.
I disagree withy the Sardinian irritation. Sardinia as the leader for unification of Italy is still 20 years in the future. In 1830 the kingdom is still under the clamp of the Restauration, and no one thinks that the Savoys might end up on the Italian throne.
He had no intention of taking Lucca. Nor Tuscany. He intended to use his French backing to follow his dream...
He ordered his generals to draw up plans for an invasion of Lombardy.
Lombardy? Taking the full blunt of Austrian counter-offensive, since he will be inavding Austrian lands? With the army of the duchy of Modena and a bunch of insurgents? Lombardy might come, in the future and if he's smart enough (but he's to be truly smart).
If you don't mind my meddling in your TL, I would make the following suggestion:
- in 1830-31 a number of insurrection took place in Italy: chiefly they happened in Romagna (which was part of the Papal states) and Genoa (under the kingdom of Sardinia, after the congress of Vienna). In OTL, the insurrections were bloodily repressed by the Austrians (and your friend Philip d'Orleans sent a naval squad to occupy Ancona, on the Adriatic litoral, and to support the repression: never mind that he sponsored the principle of non-interference). Interestingly enough, there was also another French connection: Luigi Bonaparte was one of the leaders in the Romagna insurrection.
- Suppose that Francis IV goes along with the tide: not only he sends arms and supplies to the insurgents, but he moves his army to block Austrian probes into Romagna. Philip agains sends a naval squad to Ancona, and an expeditionary force. The formal justification is to help in keeping order; however in TTL the French are really supporting the insurgents, not helping to put them down.
- This scenario also makes more sense if francis wants to have a real French support. Suppose he tries to invade Lombardy. Where are his allies coming from? Sardinia is against the insurrection, and there is no chance to use the alpine passes. Landing in northern Tuscany and then marching across the Appennines would be a logistical nightmare.
- If you want to widen the number of participants, remember that the British should still be garrisoning Corfu. A more liberal British public opinion might stampede the government in giving some support too.
- If everything goes well, and the Franco-modenese are able to coordinate their moves, Austria might get a bloody nose, and the pope too. When the dust settles, Francis is offered the crown of Cispadania (= below the Po river), as Francis I. But there must be a constitution.
- an additional possibility might be to give some support to the insurrection in Genoa, both by land, through Garfagnana and eastern Liguria and by sea (courtesy of Philip again). The insurrection is successful here too, and the grateful populace re-establish the republic of Genoa, granting however the hereditary dogal title to Francis I of Cispadania and his heirs.
A lot of ifs, predicated on a slow Austrian reaction, a very smart Francis and Philip playing ball. More credible however than an invasion of Lombardy.
Like that?
Austria is certainly having kittens, the pope is tremendously pissed off, Russia is grumbling (but it is also the epriod of the establishment of Greece, so maybe they are distracted by the east), the Bourbons in Southern Italy are quite worried; and Piedmont is certainly very much pissed off, having lost the recently acquired Liguria. But Piedmont is quite vulnerable to an alliance between France and Modena.