Medieval ruler nicknames were something else, later we just have tons of either nothing or bootlicking shit like "The great" for a ruler of Kuwait or 1/10 of Georgia or aparently every Thai king ever, but in medieval they often were more descriptive or straight up ironic. For example Charles the Bald wasn't even bald, he got this nickname because when his brothers recieved their own kingdoms he didn't, and only after many years and unsuccessful attempts he finally got his own crown.
Some Polish rulers nicknames include:
Mieszko II, officially called Lambert (his christian name), was for the longest time been called "Lazy" though to be fair pretty undeservedly
Bolesław Krzywousty (Wrymouth) - unclear if he was called that because he had deformed face or because he rarily had warm words for people, but exhumations in the place of his burial did revealed what was probably his remains and the skull did had somewhat deformed jaw.
Bolesław Rogatka (the Horned one, though better word would be Turnpike), at some point ruler of most of Poland, origins and meanings of his nick are multiple, from rampant lust and SA's, often failed adventures to the fact he used to rob people on the turnpikes, usually figuratively but also literally.
Mieszko Plątonogi (Tanglefoot) - nickname origin unclear, most possibly from being disabled and having trouble walking
Bolesław Wstydliwy (the Chaste, but better translation would be The Bashful) - he was probably impotent but paid tons of money to church and not only turned that into great pious PR but even managed to make his unfucked wife Kinga a literal saint.
Władysław Laskonogi (Spindleshanks) - was tall, and had unproportionally long legs, so much that he avoided being called the Lustful, which would be more apropriate for him.
Władysław Łokietek (The Elbow-high, but literally Little Elbow) - exhumation revealed he was around 155cm which wasn't really that short in XIII century so the nickname was either made up or came from something else.
Henryk Brodaty (the Bearded) - his beard must have been really impressive even in age of impressive beards
Bolesław Zapomniany (The Forgotten One) - could be king of Poland for few years during the turmoil after Mieszko II ran off from throne. One explanation for the uncertainity of his existence was that he was sentenced to damnatio memoriae for tyranny, but much more probable is that he simply didn't exist and was made up by later chroniclers to cover the fact Poland did not had any ruler for 4 years but didn't stopped existing and that in this time population took to arms against royalty and christianity.
Leszek Czarny (The Black) - allegedly he was wearing black all the time, he was agressive and warlike ruler conflicting with aristocracy, and he got into one of the biggest scandals in medieval Poland, openly being gay, so got slandered in chronicles by church.
Medieval ruler nicknames were something else, later we just have tons of either nothing or bootlicking shit like "The great" for a ruler of Kuwait or 1/10 of Georgia or aparently every Thai king ever, but in medieval they often were more descriptive or straight up ironic. For example Charles the Bald wasn't even bald, he got this nickname because when his brothers recieved their own kingdoms he didn't, and only after many years and unsuccessful attempts he finally got his own crown.
Some Polish rulers nicknames include: