As Frederick II, Elector of Saxony, called the Gentle, died in September 1464 his sons Ernst und Albert, had to work together with William III, Landgrave of Thuringia, called the Brave, until his death in September 1482. From that political cooperation we still have some correspondence. The dukes wrote to each other of events happening in their lands. On the 14th January 1478 William wrote to his fellow dukes about the duel between Simon of Stetten and George of Rosenberg. And he gave us the most detailed and dramatic description of such a fight in the 15th century.
And this is how he started the letter 
Den Hochgebornnen Fursten Hern Ernsten Chuerfurstenn vnnd Hern Albrechten gebrüdern Hertzogen zu Sachsen Landgraven In duringen vnnd Marggrauen zcu Miessenn vnsern liebenn Vettern
Vnnser Freuntliche dinst vnnd was wir liebs vnnd guts vermogen allezceit zuvor Hochgepornen Fursten lieben vettern vmb das geschenn slahen Jorgen von Rosinberg vnd Symons von Steten Ist vns itzund In schrifften vnd vertzeichnis zu komen, wie das ergangen vnd geendt sulle sein. Als ewr liebe In hir Ingelegter außschriefft vernemen wirdet, die wir ewr liebe zu senden nicht verhalten wollten, dovon ein wißen zu haben, dann womit wir ewr beyder liebe den wir ein frölichs nuwes Jare mit langwiriger gesuntheid vnb aller gluckseligkeid wunschen, wosten freuntlich beheglichkeit vnd gefallen zuertzeigen fundet Ir vnns allezceit In vließe geneigt
Geben zu Wymar Auf Mittwochen Felicis in Pincis Anno etc . Septuagesimok Octavo, Wilhelm von gots gnaden Hertzog zu Sachsenn Lanndgraue in duringen vnd Marggraue zu Missen
We do have some facts about Georg von Rosenberg, and about Simon of Stettin.
Georg of Rosenberg of Schipff (Schüpf) and Bocksberg (Boxberg) was a Knight and not a nice guy. In a letter of Duke Albrecht Achilles on 12thSeptember 1480 he named this knight as someone who “will cut the testicles of a cleric away”. According to Rixner and other sources the knight and his family participated in the tournaments 1481 Heidelberg, 1485 Ansbach, and Bamberg 1486 . We know that he had some trouble with Bishop Rudolf of Schwerenberg in 1487 regarding is duties (the bishop was a very combative man) . This trouble was based on raids by the Rosenbergs.
The trouble led to war and in the end the castle Bocksberg was destroyed in a siege of 21 days in 1477 (or January 1470) by the bishop and his allies (led by the well know captain Lutz Schott). The castle of Schipff was destroyed completely . Michel Beheim wrote a poem on the battle of Georg of Rosenberg in his chronicle (Heidelberg cpg335 Fol. 173r). Georg of Rosenberg was allowed to rule his country but never to build another castle, which he did at Bocksberg from March 1480 until September 1493 and so causing trouble again. In 1486 he and his fellows earned the Imperial Ban for their constant quarrel with the bishop Rudolf (Regg.F.III. H. 4 n. 932a). In Mai 1496 a document reports of a settlement between him and the city of Adelheim (OStR. I 636-639). His last naming is in 1504 in a battle at Landau. The castle on the Bocksberg was destroyed in 1523.
The opponent is called Simon of Stettin in this letter. The same man is called in Sigmund von Stetten by Ludwig von Eyb (author or owner of the Kriegsbuch MS B.26 (see Wiktenauer http://wiktenauer.com/wiki/Ludwig_VI_von_Eyb), and a tournament book). Von Eyb eye-witnessed that the duel. Rosenberg’s opponent is probably Simon IV. (died 1514) of Stetten, Künzelsau, Hohenlohe Germany.
Ludwig von Eyb reported that the fighting was secured by 600s men and took place in Ansbach under the eyes of Margrave Albrecht Achilles. The last “Ritterrecht” (right of knights) that had been allowed by the Margrave had been in 1473 in Schwabach (Mangen von Hasberg vs. Veiten von Rechberg) where Ludwig von Eyb was again a witness. Von Eyb named Marshal Conz von Luchau and Hilpolt von Hausen as the judges of this fight. And with that additional information we have a detailed description.
If we look at this case, we see that an offence led to a deadly fight with sharp weapons. Even if killing for a wired perception of honor exists until today, this comes strange to us today. We must understand that these two fighters are allies in a greater conflict. They had fought together and will fight together as comrades on the battlefield. But these men were no noble knights. These kinds of knights of the 15th century were plunderers, bandits, murderers, killers, rapists and worse. They raided peasant villages and cities, and killed for money, fame and lust. To settle a disagreement with weapons came naturally to them. The only things that made this complicated were the costs and the juridical implications of killing another noble. The life of a noble belongs to the liege lord. So killing each other without the admission of the liege lord was a real problem that could end in big trouble. But if they kill each other in a duel with the admission of the overlord they could earn fame and money. Alas these admissions were not easily given. We have reports that a knight followed his overlord for four years to get finally the authorization for a duel. Leaders do not like to throw away good fighters and they do not appreciate the change of the political power structure in their lands that usually is followed by such a duel.
The Chronicle of the duel
Simon of Stetten and Georg of Rosenberg had agreed in letters to settle their quarrel by a duel. This was not a juridical duel. So if surviving the fight the loser was not to be executed, but the winner could take the loser for ransom.
They asked the Margrave Albrecht Achilles to allow and oversee their case. And so he did in Ansbach (Onoldsbach) in January 1478. The following accurate chronicle is given by the letter of the Magrave Wiliam and the diary of Ludwig von Eyb.
The author of this article did not add anything to the description of the duel itself, even if the process of transcribing and translation may have altered the content. The aftermath of the duel was summarized.
Monday, 5th January 1478.
13:00 the first party arriving in Ansbach was Simon von Stettin. He arrived with allies and friends on XXIIII horses. They wear grey colors. They arrived in a folly mood.
15:00 like his opponent Georg of Rosenberg arrived with 220 horses. He is accompanied by his wife. Dressed in black they show humility.
They went to stay in different hostels.
17:00 Magrave Achilles send his heralds to the parties to tell them that in the morning after the early mass of the Three Kings Day, he and his council will be there to oversee the case.
Until the late night the Margrave and his council tried to persuade both knights but they insisted to fight for their cause so the Margrave agreed.
Monday, 6th January 1478.
At early morning both asked for their armor. And the armor was inspected. The armor a Harnisch consisted of Eisenhut (helmet), Bart (bevor), Pantzer (breastplate), Koller (gorget), Rücken (backplate), Krebs (cuisses), and Beinling (poleyn or greaves), Waffenhandschuhe (Handschuhe, gauntlets). The same inspection was done with the saddle, saddle girth, and the bridle.
They had two swords and draw by chance the swords which each one would fight with.
Seeing that everything was according to the laws the Margrave told Rosenberg and Stetten that the duel will be at Wednesday at 12:00.
Wednesday, 8th January 1478
11:00 The Margrave and his marshal ordered 600 men to secure the place of the fight. They stood in circles around the barriers. The marshal took the swords and sent them to the hostels of the parties. The Grießwarten (second) brought the Tartsche (shield) and the Spieß (lances and spears) into the barriers. The names of the Grießwarten were Lorenz von Eberstein (Eyb is naming Contz von Luchau), Ludwig von Hausen (Eyb: Hilpolt von Hausen). The Magrave’s herald called out the rules for the spectators: that anybody interfering with the fight by shouting, cheering, singing, waving or pointing, will be beheaded or hanged without mercy.
First Georg of Rosenberg came out of his hostel. He was dressed in a red silken gown.
12:00 Georg ordered the barrier opened for him and went in. He made the sign of the cross three times by entering. Then he brought his horse in by foot and went three times along the lane leading his horse, so that his horse will be not irritated by the armed men along the barriers. Finally he waited at his place in the barriers for his opponent to arrive.
Simon of Stetten wearing a grey gown went by foot from his hostel leading his horse. He went into the church but it was closed, so he felt on his knee in front of the church and prayed. So they opened the church and he went in, knelt in front of the altar of Saint Sebastian and spoke his prayer. He left the church mounted his horse and went into the barriers.
The Grießwarten on horses came to Simon who had to complain about hearing that Rosenberg has went up and down the lane for three times. So the Grießwarten offered him to do the same. But as Stetten went down the lane for the first time, he came to the place where Rosenberg was waiting for him. And so he decided that walking down the lane for one time is enough. So the Grießwarten came to both mounted fighters to put them on their shields. With the completion of their armor by the shields both went up and down the lanes for two or three times.
Simon of Stetten faced the galleries, the nobles and spoke: “You beloved people, the reason I will fight Georg of Rosenberg today is genuine by his huge arrogance and haughtiness. I beg you to pray to the almighty God for me because my case is righteous and true.”
Georg of Rosenberg spoke to the spectators: “You, Graves, Free Men, Knights, Squires and beloved friends! As Simon of Stetten speaks I should fight him today because of my arrogance and haughtiness, this is not true. I tell you what this fight is about. He had captured my friend and did not respect his honor; therefor I challenged him for the honor of my friend in front of my gracious master the margrave and his council. ,In front of my gracious master the count palatine and his council I have received the honor and the right to do so. Therefor I beg you for the justice of the Lord to pray at the Allmighty for me in my misery.” (Notes 1)
After that speech Simon of Stetten turned again to the spectators and spoke „What Georg of Rosenberg is telling is that I should have taken the honor and the rights of his friends away by force, but this is not true as God is my witness today.”
And both called out that God shall lead their weapons and should help them to stay unwounded. Each was given a Grießwarten as a second. The Grießwart of Simon asked him if he wanted to stay at the place he had chosen, and he agreed. And so the Grießwart of Georg spoke to him, that in the name of God he shall move to the other side of the barriers. Finally they gave them the two lances in their hands.
Now came the marshal on the lanes and shouted loudly out “Georg and Simon, mark! When the trumpets sound fight in the name of God.”
With the lance on horseback
Simon of Stetten took the lance to the hook on his breastplate and Georg took his on his legs. The trumpets sounded and they rushed against each other for several times. Georg managed to hit Simon on the shield and Simon missed and lost his shield. Without the shield Simon took the lance on his left leg and while he evaded Georg’s lance he hit him hard. George lost his Bart (bevor) and his shield. The hit had cost Simon his lance while Georg’s lance was broken. With the half lance in the hand the knight spurred his horse and rushed against his opponent. But Simon reached out for his sword and set the lance aside. So George dropped the broken lance and passing Simon he draw his sword.
With the sword on horseback
Simon turned his horse and waited for George to run his horse against him. They used the swords as lances, thrusting hard to the face. Suddenly Georg cut over the eye of Simon’s horse, it staggered and it looked like it would collapse. Georg tried to stab the horse again below the eye. But Simon defended himself so boldly that Georg was driven three or four feet away. In that maneuver Georg nearly lost his sword but managed to catch it with his left arm at the blade.
Simon’s horse became unbearably nervous. It sprang and kicked wildly against the barrier. Simon hung more from his horse than riding it. Georg followed and hit Simon with the sword near the Eisenhut (helmet). Simon was now trapped by the barriers and his opponent. Georg closed in and grabbed Simon’s head drawing it his own horse. He got a hold on the helmet and battered it, shouting out that he had captured him. Simon got hold on the cantle of Georg’s saddle with his left hand struggling. Georg increased his hold so that Simon nearly suffocated, unable to speak and to give up, but still waving his sword. Georg dropped his own sword and snatched over Simon and mangled the sword by sheer force out of his hand.
But before anybody can speak a word Simon’s horse jumped wildly and got away from Georg. After three jumps with Simon hanging on the horse he fell hard on his head. Georg followed and tried order his hors to trample on the lying men, but the horse shied back and turned wildly at two lance length. Georg was nearly unseated and tried to get from the horse. But his left foot was cached in the stirrup and so he fell hard on the side.
With the sword on foot
Simon was already standing again and saw that Georg had fallen. He began to move to the man on the ground but saw then that he had nothing in his hand. Simon wanted to equip himself with a good Reißspieß (a spear) while Georg picked himself up and his sword that he dropped before. Meanwhile the Grießwarten dismounted and joined to oversee the fight by foot. So they heard the following conversation.
As Simon grabbed one of the lances by the iron head Georg put his foot on the shaft and spoke “let it lie”. There Simon let the lance go and closed into Georg. Georg stabbed with the sword but Simon displaced the thrust with his both hands. Simon fell with both hands on Georg’s arms but was to weak. Georg stabbed Simon between the Bart (bevor) and the Eisenhut (helmet) and Simon grasped the sword with both hands and pressed it down out of the helmet again.
As they struggled and wrestled they bumped into a barrier and Georg caught Simon with his right arm under the Eisenhut (helmet) at the neck (throat) and threw him below him to the ground. Georg remained standing (or steady) and thrust the sword between the between the Bart (bevor) and the Eisenhut (helmet) to the cheek. He shouted that Simon should give up otherwise he will thrust him through the neck. There Simon screamed that the Holy Mother Mary should help him.
The Grießwarten came closer and to hear what the man was shouting the put their heads near the helmet. As they heard that the honor of Georg was established they pushed Georg away. And as the Margrave heard that Simon had submitted himself, he shouted “Separate! Separate!”. The Grießwarten helped Simon over the barriers to his friends that drove him to his hostel (probably by a cart).
George removed his helmet and laid down his sword in front of him, knelt down with folded hands and thanked the Almighty God, that he had presented him victory. Then he stood up went to the Margrave to thank him for the protection and the admission for the fight. Finally he left the barriers went to his friend and they all went to the church. After praying again he moved to his hostel and undressed his armor.
The winner takes it all?
14:00 (two hours later) Georg sent three of his friends to Simon of Stetten and let them claim the 200 Guilder he had won as a ransom. Simon spoke: “Yes I acknowledged that I do have a debt of this amount to Georg of Rosenberg. But here had been no time limit set when this had to be paid. Four or six years could be a proper time.” And they were thrown out the hostel and laughed at by him and his friends. But finally the Margrave mad the date when it should be paid (at St. Peter’s day near Heidelberg). The Margrave invited both parties to his house next morning.
Thursday, 9th January 1478
Early in the morning they arrived at the house and the Margrave settled the case finally. And by this they rode away.
Later in the same country
In the feud of the Rosenbergs against the bishop Rudolf, Simon of Stetten fought on the side of Georg of Rosenberger. They plundered several villages like Hohebach, Mäusberg, Belsenberg, Steinbach, Ohrenbach, Amrichshausen, Jungholzhausen. Rosenberg and Stetten were allies in the 20 years feud against the earls of Hohenlohe.
Books used in this posting  Herzog Albrecht der Beherzte, Stammvater des königlichen Hauses Sachsen: Eine Darstellung aus der sächsischen Regenten- Staats- und Cultur-Geschichte des XV. Jahrhunderts, grossentheils aus archivalischen Quellen, Friedrich Albert von Langenn, F.C. Hinrichs, 1838  Andermann, Kurt: Die Urkunden des Freiherrlich von Adelsheim’schen Archivs zu Adelsheim (Regesten) 1291-1875. Buchen 1995, S. 90-92.  Turniere, Sebastian Münster, 1820  Gesamtkatalog der Wiegendruck, http://gesamtkatalogderwiegendrucke.de/docs/ROSEGEO.htm, 1997  Quellen und Erörterungen zur bayerischen und deutschen Geschichte (1856)  Die Burgen, Klöster, Kirchen und Kapellen Badens und der Pfalz mit ihren Geschichten, Sagen und Märchen, Band 2, Ottmar Friedrich Heinrich Schönhuth, August von Bayer, Geiger, 1862  Des Ritters Ludwig von Eyb Denkwürdigkeiten brandenburgischer (hohenzollerischer) Fürsten herausgegeben von Constantin Hoefler, Eyb, Ludwig von – Bayreuth – Buchner – 1849
Ratzen und meus, Rats and mice
Flöch und leus, Flees and lice
Angst und sorgen, Fear and sorrows
Wecken mich all morgen. wakes me the morrows
Georg von Rosenberg (from the Zimmerische Chronik).