* Albert I of Germany ( 1255 – 1308 ), King of Germany and Archduke of Austria

The city of Lublin suffered most frequently – among others, it was burnt by the Rusyns in 1244, the Lithuanians 1255, the Prussians in 1266, and the Yotvingians in 1282.

Mindaugas had at least two wives, Morta and Morta's sister, whose name is unknown, and possibly an earlier wife ; her existence is presumed because two children – a son named Vaišvilkas and an unnamed daughter married to Svarn in 1255 – were already leading independent lives when Morta's children were still young.

Subsequently he received several ecclesiestical benefices, becoming archdeacon in Bologna ( 1244 ) and Parma ( 1244 / 48 – 1255 ), canon and chancellor of the cathedral chapter in Reims ( 1243 – 1250 ), canon and dean of the chapter in Piacenza ( c. 1247 ) and canon of the cathedral chapter in Paris ( 1244 / 45 – 1270 ).

* Frederick IV ( 1204 – 1251 / 1255 ), also Burgrave of Nuremberg ( as Frederick II ) until 1218

* Frederick V ( 1251 / 1255 – 1289 )

* January 23 – Florent of Hainaut, Prince of Achaea ( b. c. 1255 )

* 1255 – Hulagu Khan is dispatched by his brother Möngke Khan to destroy the remaining Muslim states in southwestern Asia.

* 1255 – May – William of Rubruck from Constantinople returns to Cyprus from his missionary journey to convert the Tatars of central and eastern Asia, his efforts having been unsuccessful.

* 1255 – The Gothic cathedral Cathédrale Saint-Étienne de Bourges at Bourges, France, is completed.

* 1255 – The Portuguese capital is moved to Lisbon.

* 1255 – Königsberg ( now Kaliningrad ) is founded in Prussia.

* 1255 – Batu Khan, Mongol ruler and founder of the Blue Horde ( b. c. 1205 )

* May 1 – Albert I of Germany, Duke of Austria ( murdered ) ( b. 1255 )

Albert I of Habsburg () ( July 1255 – 1 May 1308 ) was King of the Romans and Duke of Austria, the eldest son of German King Rudolph I of Habsburg and his first wife Gertrude of Hohenburg.

* January 16 – Nikephoros Choumnos, Byzantine scholar and statesman ( b. 1250 or 1255 )

* July 2 – King Adolf of Germany ( b. c. 1255 )

# Albert I of Germany ( July 1255 – 1 May 1308 ), Duke of Austria and also of Styria.

The last Grand Master of the Assassins at Alamut Imam Rukn al-Din Khurshah ( 1255 – 1256 ) was executed by the Hulagu Khan after a devastating siege

# Ferdinand de la Cerda, Infante of Castile ( 23 October 1255 – 25 July 1275 ).

## Eve de Braose ( 1227-28 July 1255 ), married Sir William de Cantelou and had descendants.

From June to July 1255 he issued 22 bulls of instruction, encouragement, and protection of the young Order.

Adolf ( or Adolph ) ( c. 1255 – 2 July 1298 ) was the King of Germany from 1292 until 1298.

* Andrey of Gorodets ( c. 1255 – 27 July 1304

1255 – 27 July 1304 ) was a Russian prince, son of Alexander Nevsky, who received from his father the town of Gorodets on the Volga.

According to historian Graham Platts, a charter was granted to a John de Beke ( or John Beck ) in 1255 to hold a weekly market in Spilsby each Monday and a three-day annual fair in July.

The general heiress of his Kingdom of Sicily and the Duchy of Swabia was his aunt Margaret, half-sister of his father Conrad IV ( the youngest but only surviving child of Frederick II and his third wife, Isabella of England ) and married with Albert, Landgrave of Thuringia since 1255.

The church of the nunnery was also used as a parish church, headed by a provost, first mentioned in 1255 ( a certain Albert ).

* Nicholas I, Duke of Troppau, natural son of king Ottokar II of Bohemia, became Duke of Troppau in Silesia ( c. 1255 – 1318 )

The succession of Theodore II was exploited by the Bulgarians, who invaded Thrace under the leadership of the young and inexperienced Michael Asen I of Bulgaria in 1255.

* Nicholas I, Duke of Troppau ( 1255 – 1318 ) ( Mikuláš I. Opavský ), the king's first-born son and also an ancestor of the Přemyslid dynasty in Opava.

The city of Landshut and Trausnitz castle were founded in 1204 by Duke Louis I. Landshut was already a Wittelsbach residence by 1231, and in 1255, when the duchy of Bavaria was split in two, Landshut also became the capital of Lower Bavaria.

For this purpose, during 1254 – 1255 Przemysł I tried to establish warmer relations with Brandenburg with the betrothal of his eldest daughter Constance with Conrad, son of John I, Margrave of Brandenburg ( the marriage took place after Przemysł I's death, in 1260 ); however, this event proved to be a political fiasco, because thanks to this union, later the House of Ascania claim rights over western Greater Poland.

In 1255, he married Margaret, the daughter of King Theobald I of Navarre and Margaret of Bourbon.

* Bridget ( Brigitte Jutta ) ( d. 4 April 1266 ), fiancée of Otto of Brunswick and Lunenburg, ∞ before 1255 Margrave John I of Brandenburg of the Johannean line Brandenburg-Stendal

* Jutta, ∞ m. 1255, John I, Margrave of Brandenburg ; 2m: Burkhard VIII of Rosenburg, Burgrave of Magdeburg

Daniel I of Galicia or Daniel Romanovych or Danylo Halytskyi () was a King of Galicia ( Halych ) ( 1205 – 1255 ), Peremyshl ( 1211 ), and Volodymyr ( 1212 – 1231 ).

This is a result of two brothers, count Walram II and count Otto I, agreeing to divide their father ’ s ( Henry II ) lands between them in 1255.

* Mari Djata I ( 1235 – 1255 )

* Uli I ( 1255 – 1270 )

Under Sundiata's successors, most notably his son Wali Keita ( r. c. 1255 – 1270 ) and his grand-nephew Kankou Musa I ( r. c. 1312 – 1337 ), the Mali Empire continued to expand, eventually creating a centralized state including most of West Africa.