March 4AD 51 – Nero, later to become Roman emperor, is given the title princeps iuventutis (head of the youth). 306 – Martyrdom of Saint Adrian of Nicomedia. 852 – Croatian Knez Trpimir I issues a statute, a document with the first known written mention of the Croats name in Croatian sources. 938 – Translation of the relics of martyr Wenceslaus I, Duke of Bohemia, Prince of the Czechs. 1152 – Frederick I Barbarossa is elected King of Germany. 1238 – The Battle of the Sit River begins two centuries of Mongol horde domination of Russia.
September 171111 – Highest Galician nobility led by Pedro Fróilaz de Traba and the bishop Diego Gelmírez crown Alfonso VII as "King of Galicia". 1176 – The Battle of Myriokephalon is the last attempt by the Byzantine Empire to recover central Anatolia from the Seljuk Turks. 1382 – Louis the Great's daughter, Mary, is crowned "king" of Hungary. 1462 – Thirteen Years' War: A Polish army under Piotr Dunin decisively defeats the Teutonic Order at the Battle of Świecino. 1543 – The first Finnish-language book, the Abckiria by Mikael Agricola, is published in Stockholm.
April 1527 – Byzantine Emperor Justin I names his nephew Justinian I as co-ruler and successor to the throne. 1081 – Alexios I Komnenos overthrows the Byzantine emperor Nikephoros III Botaneiates, and, after his troops spend three days extensively looting Constantinople, is formally crowned on April 4. 1572 – In the Eighty Years' War, the Watergeuzen capture Brielle from the Seventeen Provinces, gaining the first foothold on land for what would become the Dutch Republic.
April 171080 – Harald III of Denmark dies and is succeeded by Canute IV, who would later be the first Dane to be canonized. 1349 – The rule of the Bavand dynasty in Mazandaran is brought to an end by the murder of Hasan II. 1362 – Kaunas Castle falls to the Teutonic Order after a month-long siege. 1492 – Spain and Christopher Columbus sign the Capitulations of Santa Fe for his voyage to Asia to acquire spices. 1521 – Trial of Martin Luther over his teachings begins during the assembly of the Diet of Worms.
March 9141 BC – Liu Che, posthumously known as Emperor Wu of Han, assumes the throne over the Han dynasty of China. 1009 – First known mention of Lithuania, in the annals of the monastery of Quedlinburg. 1226 – Khwarazmian sultan Jalal ad-Din conquers the Georgian capital of Tbilisi. 1230 – Bulgarian Tsar Ivan Asen II defeats Theodore of Epirus in the Battle of Klokotnitsa. 1500 – The fleet of Pedro Álvares Cabral leaves Lisbon for the Indies. The fleet will discover Brazil which lies within boundaries granted to Portugal in the Treaty of Tordesillas in 1494.
August 24367 – Gratian, son of Roman Emperor Valentinian I, is named co-Augustus at the age of eight by his father. 394 – The Graffito of Esmet-Akhom, the latest known inscription in Egyptian hieroglyphs, is written. 410 – The Visigoths under king Alaric I begin to pillage Rome. 1185 – Sack of Thessalonica by the Normans. 1200 – King John of England, signer of the first Magna Carta, marries Isabella of Angoulême in Angoulême Cathedral. 1215 – Pope Innocent III issues a bull declaring Magna Carta invalid.
April 28224 – The Battle of Hormozdgan is fought. Ardashir I defeats and kills Artabanus V effectively ending the Parthian Empire. 357 – Emperor Constantius II enters Rome for the first time to celebrate his victory over Magnus Magnentius. 1192 – Assassination of Conrad of Montferrat (Conrad I), King of Jerusalem, in Tyre, two days after his title to the throne is confirmed by election. The killing is carried out by Hashshashin.
April 261336 – Francesco Petrarca (Petrarch) ascends Mont Ventoux. 1478 – The Pazzi family attack on Lorenzo de' Medici in order to displace the ruiling Medici family kills his brother Giuliano during High Mass in Florence Cathedral. 1564 – Playwright William Shakespeare is baptized in Stratford-upon-Avon, Warwickshire, England (date of birth is unknown). 1607 – The Virginia Company colonists make landfall at Cape Henry. 1721 – A massive earthquake devastates the Iranian city of Tabriz.
March 81010 – Ferdowsi completes his epic poem Shahnameh. 1126 – Following the death of his mother, queen Urraca of León, Alfonso VII is proclaimed king of León. 1262 – Battle of Hausbergen between bourgeois militias and the army of the bishop of Strasbourg. 1558 – The city of Pori (Björneborg) is founded by Duke John on the shores of the Gulf of Bothnia. 1658 – Treaty of Roskilde: After a devastating defeat in the Northern Wars (1655–1661), Frederick III, the King of Denmark–Norway is forced to give up nearly half his territory to Sweden.
March 291430 – The Ottoman Empire under Murad II captures Thessalonica from the Republic of Venice. 1461 – Battle of Towton: Edward of York defeats Queen Margaret to become King Edward IV of England, bringing a temporary stop to the Wars of the Roses. 1549 – The city of Salvador, Bahia, the first capital of Brazil, is founded. 1632 – Treaty of Saint-Germain is signed returning Quebec to French control after the English had seized it in 1629. 1792 – King Gustav III of Sweden dies after being shot in the back at a midnight masquerade ball at Stockholm's Royal Opera 13 days earlier.
