Today is the anniversary of a couple of events that wound up having repercussions far beyond what most contemporaries probably thought they would, and so I’m not going to take much time describing what they actually were so much as noting that they happened and explaining why they mattered.
The Battle of Alcácer Quibir in 1578 was actually fought over a Moroccan succession crisis, but its result wound up profoundly impacting the political situation in Portugal. The Bani Zaydan, also known as the Saadis, were a dynasty that ruled Morocco for about 100 years from the second half of the 16th century through the first half of the 17th (they controlled southern Morocco in the first half of the 16th century and grew from there). Under Muhammad al-Shaykh (d. 1557) they were able to eliminate both the Ottoman-backed Wattasid Dynasty of northern Morocco and the Portuguese colonial presence in coastal cities/fortresses like Agadir, Asilah, and the place where this battle was fought, al-Qasr al-Kabir (or Alcácer Quibir for the Portuguese).
After Muhammad al-Shaykh came his son, Abdallah al-Ghalib (d. 1574), who consolidated his father’s gains and defended them against the Ottomans in particular. When he died, he was succeeded by his oldest son, Abu Abdallah Mohammed II (d. 1578, which is a spoiler), and here’s where the Saadis ran into some trouble. Abdallah al-Ghalib’s brother, Abu Marwan Abd al-Malik I (d. 1578, also a spoiler–sort of), immediately headed off to Constantinople (and yes, the Ottomans still called it Constantinople, don’t believe the hype or the song lyrics) to ask for help knocking his nephew off the throne. The Ottomans obliged, and send Abu Marwan back to North Africa, where he raised an army with Ottoman help, then invaded Morocco and captured Fez in 1576. Abu Abdallah, now a former sultan but still very much alive, decided to head off in search of his own powerful patron, and who better to help him than the kingdom still stinging from losing most of its coastal holdings in Morocco just a couple of decades earlier?
The very young (24) Sebastian I of Portugal (d. 1578, again a spoiler) received Abu Abdallah and decided to help put him back on the throne of Morocco. He’d already been getting prodded by his advisers to do something about the Moroccan problem, which was now looking like a critical threat since Abu Marwan was an Ottoman client, which meant a direct Ottoman threat against the parts of the Moroccan coast Portugal still held. The arrival of Abu Abdallah seemed like a perfect opportunity to not only regain Portugal’s lost holdings, but to put a Portuguese client on the Moroccan throne to boot. So Sebastian put together an army (around 18,000 men) and a fleet large enough to carry it, and sailed it to one of the few Moroccan ports still in Portuguese hands. There he met Abu Abdallah, who had another ~6000 men with him, and the combined army marched off to meet Abu Marwan’s forces (a much larger army, probably at least 3 times what Sebastian had) near Alcácer Quibir.
Although we’re well into the era of gunpowder weapons and tactics by now, the battle seems to have gone according to a very old script: the army with a large cavalry, Abu Marwan’s, surrounded and thoroughly decimated the army without cavalry. Abu Abdallah died crossing a river while trying to flee, and though the gravely ill Abu Marwan also died, though in this case his death just happened to coincide with the battle (well, the exertion of marching off to fight and preparing his men for the fight certainly contributed to his demise, but he didn’t die in battle), his brother, Ahmad al-Mansur (d. 1603) succeeded him and Saadi Morocco was peaceful again. Ahmad actually had quite a successful career as sultan, conquering (albeit briefly) the once-powerful Songhai Empire in Mali among other achievements.
The real fallout of the battle happened, as I say, in Portugal. Sebastian was probably killed in the battle, though in point of fact his body was never recovered and legends persisted in Portugal that he would [extremely dramatic voice] RETURN HEROICALLY ONE DAY IN THE HOUR OF HIS PEOPLE’S GREATEST BLAH BLAH BLAH (plenty of con men over the ensuing decades tried to claim that they were the returned Sebastian). He died, though, really. Or maybe he always wanted to be a hermit, so he took advantage of the chaos of the battle and fled into the desert. Either way, he wasn’t ruling Portugal anymore. And, because he had no heir to speak of, neither was anybody else. His uncle, Henry, who also had no heir and was in fact a Catholic Cardinal before this all happened, took the throne, but only lasted until 1580 before he expired. His ~2 years in power were spent desperately trying to pay off the debt incurred by Sebastian to pay for his little adventure in Morocco.
When Henry died, Portugal was invaded by Philip II of Spain (d. 1598), who was Sebastian’s uncle, and Philip II of Spain quickly also became Philip I of Portugal. You maybe have heard about the Iberian Union, which lasted until 1640, and/or the 1640-1668 Portuguese Restoration War, which broke up the Iberian Union? There’s a strong possibility that neither of those things would have happened had it not been for the otherwise fairly unremarkable Battle of Alcácer Quibir.
The 1791 Treaty of Sistova is, if anything, even more unremarkable than the Battle of Alcácer Quibir. It ended the also unremarkable Austrian-Ottoman War of 1787-1791, which started when the Habsburgs jumped into the middle of a war between the Ottomans and the Russians in order that they might gobble up some spoils once the Ottomans had been defeated. The end result was a technical Ottoman defeat, in that they lost Belgrade as well as some gains they’d made across the Danube River early in the war, but it wasn’t anything particularly dramatic. Austria, meanwhile, became desperate to end the war, because apparently some kind of revolution in France had broken out in the meantime and the Habsburgs could see that it was going to require all of their attention. Also, the Habsburgs were trying to negotiate a deal with the increasingly powerful Prussians to jointly oppose the French Revolution and to agree not to got to war with each other, and part of that agreement required both kingdoms to give up any designs on eastern expansion.
So in the treaty, the Habsburgs gave Belgrade back to the Ottomans (screwing over, incidentally, a lot of Serbs whom the Habsburgs had recently encouraged to rebel against Ottoman control) and settled for a couple of very minor territorial concessions, a sort-of reward for their sort-of victory. What makes Sistova worth commemorating is not anything about the treaty itself, but rather that it, quite unexpectedly, represents the end of the long series of Habsburg-Ottoman wars. The two empires had been in steady conflict, hot and cold, on land and at sea, since the first Battle of Mohács in 1526–so for 265 years–and suddenly it was all over, in perhaps the most nondescript way possible. While the Ottomans began their long conflict with the Habsburgs as the clearly dominant power (though the Habsburgs were no pushovers, as, for example, they proved at Lepanto), when it ended it was the Habsburgs who were the stronger of the two–though, to be fair, both empires had seen better days. The Ottomans would be occupied fighting Russia throughout the 19th century, while the Habsburgs would turn most of their attention to happenings in western Europe, to separatist movements inside their empire, and to the continued rise of Prussia. World War I saw both of the empires fighting in the same war again, but this time on the same side, and neither one of them would survive that war’s end.