section_path: History/Middle Ages (895–1526)/Age of Árpádian kings
section_name: Age of Árpádian kings
paragraph_text: Age of Árpádian kings
  
  In 972, the ruling prince (Hungarian: fejedelem) Géza of the Árpád dynasty officially started to integrate Hungary into Christian Western Europe. His son Saint Stephen I became the first King of Hungary after defeating his pagan uncle Koppány. Under Stephen, Hungary was recognised as a Catholic Apostolic Kingdom. Applying to Pope Sylvester II, Stephen received the insignia of royalty (including probably a part of the Holy Crown of Hungary) from the papacy.
  
  By 1006, Stephen consolidated his power and started sweeping reforms to convert Hungary into a Western-style feudal state. The country switched to using Latin for administration purposes, and until as late as 1844, Latin remained the official language of administration. King Saint Ladislaus completed the work of King Saint Stephen, consolidating the Hungarian state's power and strengthening Christianity. His charismatic personality, strategic leadership and military talents resulted in the termination of internal power struggles and foreign military threats. The wife of the Croatian king Demetrius Zvonimir was Ladislaus's sister. At Helen's request, Ladislaus intervened in the conflict and invaded Croatia in 1091. The Kingdom of Croatia entered a personal union with the Kingdom of Hungary in 1102 with the coronation of King Coloman as "King of Croatia and Dalmatia" in 1102 in Biograd.
  
  One of the most powerful and wealthiest king of the Árpád dynasty was Béla III, who disposed of the equivalent of 23 tonnes of silver per year, according to a contemporary income register. This exceeded the income of the French king (estimated at 17 tonnes) and was double the receipts of the English Crown. Andrew II issued the Diploma Andreanum which secured the special privileges of the Transylvanian Saxons and is considered the first autonomy law in the world. He led the Fifth Crusade to the Holy Land in 1217, setting up the largest royal army in the history of Crusades. His Golden Bull of 1222 was the first constitution in Continental Europe. The lesser nobles also began to present Andrew with grievances, a practice that evolved into the institution of the parliament (parlamentum publicum).
  
  In 1241–1242, the kingdom received a major blow with the Mongol (Tatar) invasion. Up to half of Hungary's population of 2 million were victims of the invasion. King Béla IV let Cumans and Jassic people into the country, who were fleeing the Mongols. Over the centuries, they were fully assimilated. After the Mongols retreated, King Béla ordered the construction of hundreds of stone castles and fortifications, to defend against a possible second Mongol invasion. The Mongols returned to Hungary in 1285, but the newly built stone-castle systems and new tactics (using a higher proportion of heavily armed knights) stopped them. The invading Mongol force was defeated near Pest by the royal army of King Ladislaus IV. As with later invasions, it was repelled handily, the Mongols losing much of their invading force.