What I'm picking up is that unless Philippe's wife survives the disease that killed her at 26 (like her sister, aunt and grandmother, creepy) or she's already married, he's marrying La Farnese. But considering that OTL one of the other matches proposed for Elisabetta was with the Hereditary Prince of Modena (OTL Francesco III), might we see her married to Anna Maria and Francesco II's son? Or would that be a bridge too far and someone - whether Bourbon or Habsburg IDK - would object? I mean, history has had enough happy accidents where the throne of a country comes to someone out of the clouds - so no one would be hugely objecting if the marriage happens before 1711, but once it does, alt-Francesco III and Elisabetta's kids are heirs to Modena, Tuscany, Parma and Piacenza. How would a d'Este let's call it the kingdom of Etruria*-entity fare?
*Comes from an old TL I saw where the duchy of Mantua is united with Modena, Reggio & Guastalla into a grand duchy of Etruria by the prince de Condé when he inherits it as the nearest heir.
I would like very much to see a re-vitalized House of Este consolidate a state in Emilia and Tuscany: the plain south of the Po river is very productive, and the string of cities (Piacenza, Parma, Reggio and Modena leaving aside Bologna) have a long tradition of urbanization and were generally prosperous, barring the times of bad government and the periodic incursions of major powers; the same can be said of Tuscany, of course, and good relations (or even better political unity) between the two sides of the Appennine mountains would give a boost to commerce, using Leghorn as main port. Incidentally the two sides of the Appennine were the heartland of Canossa domains in the late 10th and 11th centuries. The house of Este was also the most ancient Italian dynasty (even older and with better credentials than the Savoy): the Este are descendants of the Obertenghi, who were Margraves (military and civilian representativesof the HR emperor) of the Ligurian March (which included Lombardy and eastern Liguria from ca. 960 to the late 12th century), and took the family name from the castle of Este in Veneto which became more important with the establishment of commune in Milan and Genoa). A branch of the Este inherited the ducal throne of Bavaria (Welf IV, son of Alberto Azzo d'Este, Margrave of Milan), while the main Italian branch became lords of Ferrara, Reggio and Modena.
I do believe there is a possibility to establish this Este dominion in the first half of the 18th century, although it will require a significant amount of 20/20 hindsight and a moderate suspension of disbelief.
The two key players in this ATL would be Anne Marie Louise de' Medici (dowager duchess of Modena and Reggio) and cardinal Giulio Alberoni, prelate diplomat and politician, born in Piacenza in 1664 and who died in the same city in 1752, who was one of the shakers-and-movers of European politics between 1706 and 1720 and for a time was prime minister of Spain (and was also the instigator of the marriage between Elisabetta Farnese and Philip V of Spain, as well as of the Spanish attempts to reverse the agreements of the peace of Utrecht with the invasion of Sardinia and Sicily in 1717-18. ITTL card. Alberoni will still be a power to be reckoned with, although it may look like that his role as chief minister of the Este state will not favourably compare withhis OTL role at the court of Madrid: OTOH IOTL Alberoni was forced to take responsibility for the bungled Spanish attempt to reverse Utrecht (even if he was not the main culprit for the ill-advised venture) but it is to be hoped he might be able to avoid the difficulties of his OTL life post-1720.
Anne Marie will certainly like TTL much better than OTL: she will be able to have children and also to exert real political power, first as Regent for her underage son Francesco and later on as his most trusted advisor, and with a little luck she may be able not only to save her beloved Tuscany but alsoto see one (or both) of her sons on a throne.
Other key players (in the Italian context: the main players in Europe will stay the same as IOTL, at least for the first 15-20 years) will certainly be two popes (Innocent XII and Clement XI), the Este cardinal (Rinaldo, who IOTL renounced his cardinalate to become duke of Modena upon the death of his brother Francesco in 1695 but ITTL will remain a cardinal and will play a role in the Regency first and later as a support for his nephew Francesco III), Francesco Farnese, duke of Parma, his niece Elisabetta Farnese (who will not become queen of Spain, but hopefully will have some compensations) and the Savoyard Fox, Vittorio Amedeo II duke of Savoy).
My idea (which obviously needs to be fleshed up and researched) would start like this:
- Anne Marie accepts to marry Francesco II of Modena in 1686, whose candidacy was supported by France and England. The emperor accepts, after having been promised half the dowry (300,000 ecus) granted by Cosimo III to his daughter. AML had been promised in marriage to Vittorio Amedeo of Savoy in 1683, but the agreement had been cancelled due to the opposition of the mother of the duke (a French princess) and of France. No better outcome had resulted from the talks with Spain (Charles II was looking for a new wife). [Both failures happened IOTL too; the difference is that ITTL AML accepts Francesco]
- Francesco II of Modena dies in 1695 on schedule, but notwithstanding its short duration and the bad health of the duke the marriage is happy and blessed by 4 children (two sons, Francesco and Cosimo, and two daughters, Isabella and Maria). AML thrives, loved by the people of the duchy as well as close to her homeland and able to exert a beneficial influence on her father Cosimo (AML still influenced Cosimo even IOTL from her new home in the Palatinate, but it is quite obvious that ITTL she's much closer and the four grandchildren will also have a beneficial influence on the old grand-duke). Upon the death of Francesco II a council of Regency is formed (the heir, Francesco, is not yet 7 years old and the Regency will continue until major age, at 15): AML and cardinal Rinaldo d'Este dominate the council, and are quite able to cooperate well. Rinaldo moves from Rome to Modena, to better participate in the regency. In Parma Francesco Farnese is crowned duke as IOTL (both his father Ranuccio and his elder brother Odoardo die in 1694, within a few months of each other). In December 1695 FF decides to marry the widow of Odoardo, Dorotea Maria of Neuburg in order to be able to keep her dowry (Parma is in dire need of money), even if she's 9 years older than him, and adopts Elisabetta, his deceased brother only surviving daughter (Odoardo's son from Dorotea died very young in 1693). [all events at the ducal court of Parma are OTL]
- the war of the League of Augsburg proceeds as per OTL, and ends inconclusively in 1697 with the peace of Rjswick. Parma, Modena and Tuscany are largely unaffected by the war (exception made for the continuous pressures that the emperor puts on his Italian fiefs to contribute to the war expenses). VA of Savoy participates on the side of the League as per OTL, and ends up with substantially good results (he gains the fortress of Pinerolo, but more importantly he gets to be known in European politics). VA is not considered a ruler who can be trusted: he's joined the anti-French League late, in 1690, and there have been fears that French troops might turn out in the duchies; then he agreed a peace with France on his own terms, and there is a potentially troublesome rumor that one of the terms of the peace is that France and Savoy will "act" to protect Italian neutrality against third parties.
- 1696-1700: with the support of her brother-in-law card. Rinaldo, AML dedicates herself to improve the finances of the duchy, and the court enjoys a moderate renaissance. Liberal elements from Florence move to Modena to escape the bigot and oppressive grand-ducal court. Her brother Ferdinand, the heir to the grand-duchy is one of these, and AML is worried by the horrible news about her brother's marital life: the marriage to Violante of Bavaria has been a disaster, and the future does not promises anything better. Even more appalling are the rumors about the sexual preferences of Ferdinando (and of his younger brother Gian Gastone too). Thanks to the efforts of Rinaldo, relations with the Roman Curia are good, and also the relations with Parma are much improved. Rinaldo renews his old friendship with Alessandro Roncovieri, bishop of Borgo San Donino near Piacenza. In 1697 he meets (and is impressed) by a young cleric who is a protege of the bishop: Giulio Alberoni, who is becoming well known and respected at the ducal court in Parma. AML makes also a point to get to know young Elisabetta, who might turn out to be more than a pawn in the game of thrones: the duchess of Parma is quickly pushing 30s, there's be no news of pregnancies since her marriage to Francesco Farnese and she's also known as a dour and cold woman. Antonio, FF's brother and heir to the duchy, does not show any interest in politics, and even less interest in getting married. He's still young, but does not promise a lot. Elisabetta is often a guest at the court of Modena, and AML considers her options: Elisabetta is second in the succession line of Parma, and has also a potential claim on Tuscany through her grandmother. However dynastic considerations are not her only worry: the disasters of the war of Mantua happened just 70 years ago, and also during the last brush-up French and Imperial troops were passing through Parma and Modena territories, requisitioning foodstuff at gun point and forcing war contributions. Rinaldo shares her worry, and has started to send feelers to Rome to search for a solution which would protect the minor states in Italy.
- 1700: pope Innocent XII dies on 27 September, and the new pope, Clement XI is chosen after two weeks of Conclave. The election was dominated by French prelates, and the king of France vetoed from the beginning the election of cardinal Galeazzo Marescotti, considered to be too hard to influence. Clement XI was made up of less stern stuff. There was another death that was much more momentous and had a much more significant impact on European history: Charles II of Spain died without direct heirs on 1st November 1700. While the death was not unexpected (the Powers had been trying for a long time to find an acceptable solution to the Spanish succession), the failures of diplomacy made a general war unavoidable: Charles II had always opposed a partitioning of the Spanish empire and had chosen as heir his grand-nephew Joseph Ferdinand Leopold of Bavaria, but he had refused to accept the partition agreed by the Powers (treaty of The Hague, 1st October 1698). On 11th November 1698 Charles II declared that Joseph Ferdinand would be his sole heir, but JF died in February 1699, effectively annulling any previous agreement. There were other attempts to reach an agreement on a partition, but there was no way to convince Charles II to accept: in the end upon the advice of pope Innocent XII the king prepared a last will in favor of his grand-nephew Philippe of Anjou, naming him sole heir and only vetoing the union of the French and Spanish crown. The final version of the testament (prepared with the contribution of card. Giovanni Francesco Albani, who will become Clement XI in November 1700) was read in public on 2nd November 1700: the war of Spanish succession was ready to start.