1185 – 1261 ), Pope from 1254 until his death

* 1228 – Conrad IV of Germany ( d. 1254 )

* Conrad II of Jerusalem ( 1228 – 1254 )

# Margaret of France ( 1254 – 71 ), married John I, Duke of Brabant

Marco Polo (; ; September 15, 1254 – January 9, 1324 ) was a Venetian merchant traveler whose travels are recorded in Il Milione, a book which did much to introduce Europeans to Central Asia and China.

* 1254 – Serbian King Stephen Uroš I and the Republic of Venice sign a peace treaty.

* 1254 – Marie of Brabant, Queen of France ( d. 1321 )

1185 – 25 May 1261 ) was Pope from 1254 until his death.

* A. Paravicini Bagliani, Cardinali di curia e familiae cardinalizie dal 1227 al 1254, Padova 1972, p. 358 – 365

Cardinali di curia e familiae cardinalizie dal 1227 al 1254 in series Italia Sacra vols 18 – 19 ( Padua: Antenore 1972 ) A standard account.

* Iben Fonnesberg ‐ Schmidt, The Popes and the Baltic Crusades 1147 – 1254 ( Leiden, Brill.

Pope Innocent IV ( c. 1195 – 7 December 1254 ), born Sinibaldo Fieschi, was Pope from 25 June 1243 until his death in 1254.

Like Pope Innocent III ( 1198 – 1216 ), Pope Gregory IX ( 1227 – 1241 ) and Pope Alexander IV ( 1254 – 1261 ), he was a member of the family of the Conti, counts and dukes of Segni.

* 1254 – Marco Polo, Italian explorer.

* 1248 – 1254 — Seventh Crusade captures Egyptian Ayyubid port city of Damietta, Crusaders ultimately withdraw.

* 1254 – King Louis IX of France, having exhausted his funds and being needed at home, abandons the Seventh Crusade ( which he had conducted first in Egypt and then Syria ) and returns to France.

* 1254 – King Louis IX of France expels all Jews from France.

* 1254 – In England, an important step in the evolution of the Parliament and Peerage occurs, as lesser barons are replaced on the King's Council by elected representatives from shires and cities.

* 1254 – The classic Japanese text Kokin Chomonjo is completed.

* 1254 – The Horses of Saint Mark, once supposed to have adorned the Arch of Trajan in ancient Rome, are installed at Saint Mark's Basilica in Venice.

* 1254 – Construction is begun on the Cathedral of Saint Martin in Utrecht.

The Great Interregnum, a period in which there were several elected rival kings non of whom was able to achieve any position of authority, followed the death of Frederick's son King Conrad IV of Germany in 1254.

Therefore, after a failed agreement with Charles of Anjou, he invested that kingdom to Edmund, the nine-year-old son of King Henry III of England, on 14 May 1254.

King Louis again disapproved, and on his return from Outremer in 1254 he returned Hainaut to John.

In 1254, he was excommunicated by Pope Innocent IV as a supporter of King Conrad, due to ongoing political conflicts between the Emperor, who held the Kingdom of Sicily and wanted to reestablish his power in the Imperial Kingdom of Italy, especially in the Lombardy region, and the Papacy, whose States lay in between and feared being overpowered by the Emperor.

In 1254, English fears of a Castilian invasion of the English province of Gascony induced Edward's father to arrange a politically expedient marriage between his fourteen-year-old son and Eleanor, the half-sister of King Alfonso X of Castile.

With the death of Ottokar the first line of rulers of Styria became extinct ; the region fell successively to the Babenberg family, rulers of Austria, as stipulated in the Georgenberg Pact ; after their extinction to the control of Hungary ( 1254 – 60 ); to King Ottokar of Bohemia ; in 1276 to the Habsburgs, who provided it with Habsburgs for Styrian dukes during the years 1379-1439 and 1564-1619.

In 1254 Alfonso X signed a treaty of alliance with the King of England and Duke of Aquitaine, Henry III, supporting him in the war against Louis IX of France.

Conrad ( 25 March 1252 – 29 October 1268 ), called the Younger or the Boy, but usually known by the diminutive Conradin (, ), was the Duke of Swabia ( 1254 – 1268, as Conrad IV ), King of Jerusalem ( 1254 – 1268, as Conrad III ), and King of Sicily ( 1254 – 1258, de jure until 1268, as Conrad II ).

Ingeborg died in 1254 and in 1261 Birger married the widow of King Abel of Denmark, the Danish queen dowager, Matilda of Holstein.

Coat of arms of Charles II of Naples. Charles II, known as " the Lame " ( French le Boiteux, Italian lo Zoppo ) ( 1254 – 5 May 1309 ) was King of Naples, King of Albania, Prince of Salerno, Prince of Achaea and Count of Anjou.

An order from King Henry III in 1225 allowed the collection of donations from across the island for reconstruction for a period of four years, and the work, in the Early English Gothic style, lasted at least until rededication in 1254.

In 1603 the first Western publication on the topic of the Assassins was authored by a court official for King Henry IV and was mainly based on the narratives of Marco Polo ( 1254 – 1324 ) from his visits to the Near East.

After the death of the German King Konrad IV in 1254, Ottokar also hoped to obtain the Imperial dignity for himself, but his election bid was unsuccessful and Richard of Cornwall was elected instead.

King Henry III then passed the Lordship of Chester, but not the title of Earl, to his son the Lord Edward in 1254 ; as King Edward I he in turn conferred the title and the lands of the Earldom on his son, Edward, the first English Prince of Wales.

In 1254 Afonso III summoned cortes to Leiria, in which the chief cities were represented, as well as the nobles and clergy.

Following the reversion of the Earldom of Chester to the crown, in 1254 Henry III passed the Lordship of Chester ( but not the title of Earl ) to his son Edward, who as Edward I bestowed the Earldom of Chester on his son Edward when he created him the first Prince of Wales in 1301.

** Margaret of Savoy ( d. 1254 ), married firstly on December 9, 1235 Boniface II of Montferrat, married secondly Aymar III, Count of Valentinois

* Robert Forthington ( 1232 – 1254 ), or Robert III.

On the death of John III on November 4, 1254, Theodore II was acclaimed emperor by the army and the court, but was crowned only after the appointment of a new patriarch, Arsenios Autoreianos, in 1255.

John III Doukas Vatatzes, Latinized as Ducas Vatatzes (, Iōannēs III Doukas Vatatzēs, c. 1192, Didymoteicho – 3 November 1254, Nymphaion ) was Emperor of Nicaea 1221 – 1254.

His successor, Henry III also spent large sums on Lancaster: £ 200 in 1243 and £ 250 in 1254 for work on the gatehouse and creating a stone curtain wall.

* John III Ducas Vatatzes ( 1222 – 1254 )

After Hubert de Burgh, the Three Castles were held in Royal hands, and in 1254 Henry III granted them to his eldest son, the future Edward I.

In 1254 he organized an armed expedition against Henry III the White, destroying part of the Bishopric of Wrocław goods ( i. e. Oleśnica ), for which Przemysł I was excommunicated, and the penalty was only removed after the Greater Poland Duke repared the damages in the Church states.

Two others, Cencio Savelli, who was elected as Pope Honorius III in 1216, and Rinaldo Conti di Segni, elected as Pope Alexander IV in 1254, did not occupy that post at the time of their elections to the papacy ( Cencio was Camerlengo from 1188 until 1198, while Rinaldo from 1227 until 1231 ).

* John III Doukas Vatatzes ( c. 1192 – 1254 ), Emperor of Nicaea

William III de Ferrers, 5th Earl of Derby ( 1193 – 28 March 1254 ) was an English nobleman and head of a family which controlled a large part of Derbyshire including an area known as Duffield Frith.