The Burning of Mondragon - 1448
Toti Martinez de Lezea wrote a fantastically researched novel 'El Senor de la Guerra' - the War Lord - based on true events in early 15th century Spain. The book blends true historical characters, events and places with the romantic characters needed to spice it up a bit.
Although it seems this feudal area did not need much spicing up - around Mondragon between Bilbao and Pamplona, now in Guipuzcoa in the Basque Country. Everbody and everything belonged the the lord of the manor, smaller lords belonged to bigger lords, and everybody was in one of two bands - the Gamboinos (led by a nasty succession of lords by the name of Guevara, Lords of Onate) and the Onacinos (those of Gonzalez de Butron). Both parties had been at 'war' for nearly 200 years and nobody could really remember why it all started and why anyone was in one party or the other. Everything and everybody belonged to the Lord, to do as he wished. And wished they didn't!
The feud simmered along over the years with occasional flare-up moments like a street fight a la Romeo and Juliet, or the physical buring of an opposition Manor or business. Occasionally both parties were summoned to fight for the Royal army, which they must've done without speaking too much.
Then Pedro Velez de Guevara came to the head of the band after his father was killed in royal service, and started ramping up atrocities - both against his own peasants and by taking things by force from the opposition. Everything ramped up until there was a massive battle involving 100s of people and hired thugs at Mondragon, during which the whole town was burned in 1448. The book covers a period from about 1430 to 1448.
The King and the Constable of Castille finally had to intervene. Troops came in and trials were held, and summary death sentences past. But these were soon forgotten and remitted amid the politics and influences of the time, and the fact parties in the court needed the support of the feudal lords. So things settled down again to the fedal system, and with the death of Juan II in 1454 and the accession of Enrique VI, Pedro was back in favour again.
Of course more control must've been exercised under Isabella (and Fernando) and then under the united Spanish empire of Carlos, but I see the Lordship of Onate carried on through the centuries, helping the Carlists during the Carlist wars. Onate was finally annexed by Guipuzcoa in 1845, which the people had wanted for about 600 years! On condition that the Lord was paid 20,000 reales annually and a new coach road built near Onate. Furthermore he was granted power to be a member of the ruling council and sit at the left hand of the Corregedor of Guipuzcoa, the King's governor.
But the book is really well constructed historically, despite being a novel, and it brings home what a ghastly system it must have been to live under.