Ottoman armies had overrun all of Croatia south of the Sava River in the early sixteenth century and slaughtered a weak Hungarian force at the Battle of Mohács in 1526.

Buda is captured in 1541; Turkish marauders then advance toward Austria.

After Mohács, Hungarian and Croatian nobles had elected the Habsburg Ferdinand I of Austria king of Hungary and Croatia.

To tighten its grip on Croatia and solidify its defenses, Austria restricts the powers of the Sabor, establishes a military border across Croatia, and recruits Germans, Hungarians, and Serbs and other Slavs to serve as peasant border guards.

This practice is the basis for the ethnic patchwork that survives today in Croatia, Slavonia, and Vojvodina.

Austria assumes direct control of the border lands and gives local independence and land to families who agree  to settle and guard those lands.

The area that they settle becomes known as the Military Frontier Province.

Orthodox border families also win freedom of worship, which draws stiff opposition from the Roman Catholic Church.

Religious ferment in Europe affects Croatian culture in the sixteenth century.

Many Croatian and Dalmatian nobles embrace the Protestant Reformation in the mid-sixteenth century, and in 1562 Stipan Konzul and Anton Dalmatin publish the first Croatian Bible.

The Counterreformation begins in Croatia and Dalmatia in the early seventeenth century, and the most powerful Protestant noblemen soon reconvert.

In 1609 the Sabor votes to allow only the Catholic faith in Croatia.

The Counterreformation enhances the cultural development of Croatia.

Jesuits found schools and publish grammars, a dictionary, and religious books that help hape the Croatian literary language.

Franciscans preach the Counterreformation in Ottoman-held regions.

Turkish inroads in Croatia and Austria also trigger price increases for agricultural goods, and opportunistic landowners begin demanding payment in kind, rather than cash, from serfs.

Rural discontent explodes in 1573 when Matija Gubec leads an organized peasant rebellion that spreads quickly before panic-stricken nobles are able to quell it.

The fortress of Karlovac, located southwest of Zagreb at the confluence of the Korana and Kupa rivers and built in 1579 to stem the advance of the Turks, is named for the Habsburg archduke Charles, the first commander of the military frontier against the Turks.

Venice repulses Ottoman attacks on Dalmatia for several centuries after the Battle of Mohács, and it had helped to push the Turks from the coastal area after 1693, but by the late eighteenth century, trade routes have shifted, Venice has declined, and Dalmatian ships stand idle.

Napoleon ends the Venetian Republic and defeats Austria; he then incorporates Dalmatia, Dubrovnik, and western Croatia as the French Illyrian Provinces.

France stimulates agriculture and commerce in the provinces, fights piracy, enhances the status of the Orthodox population, and stirs a Croatian national awakening.

In 1814 the military border and Dalmatia return to Austria when Napoleon is defeated; Hungary regains Croatia and Slavonia.

In 1816 Austria transforms most of the Illyrian Provinces into the Kingdom of Illyria, an administrative unit designed to counterbalance radical Hungarian nationalism and co-opt nascent movements for union of the South Slavs.

Austria keeps Dalmatia for itself and reduces the privileges of the Dalmatian nobles.

The siege of Vienna had been the high-water mark of Ottoman expansion in Europe, and its failure has opened Hungary to reconquest by the European powers.

In a ruinous sixteen-year war, Russia and the Holy League—composed of Austria, Poland, and Venice, and organized under the aegis of the pope—finally drive the Ottomans south of the Danube and east of the Carpathians.

Under the terms of the Treaty of Karlowitz in 1699, the first in which the Ottomans acknowledge defeat, Hungary, Transylvania, and Croatia are formally relinquished to Austria.

Poland recovers Podolia, and Dalmatia and the Morea are ceded to Venice.

Russia receives the Azov region in a separate peace the next year.

The last of the Koprulu rulers falls from power when Mustafa II (r. 1695-1703) is forced by rebellious janissaries to abdicate.

Effective control of the government passes under Sultan Ahmed III (r. 1703-30) to the military leaders.

His reign is referred to as the "tulip period" because of the popularity of tulip cultivation in Istanbul during these years.

Western forces had routed a Turkish army besieging Vienna in 1683, then begin driving the Turks from Europe.

In the 1699 Treaty of Karlowitz, the Turks cede most of Hungary, Croatia, and Slavonia to Austria, and by 1718 they no longer threaten Dalmatia.

During the advance, Austria expands its military border, and thousands of Serbs fleeing Turkish oppression settle as border guards in Slavonia and southern Hungary.

As the Turkish threat wanes, Croatian nobles demand reincorporation of the military border into Croatia.

Austria, which uses the guards as an inexpensive standing military force, rejects these demands, and the guards themselves oppose abrogation of their special privileges.

Thousands of Serbs fleeing Turkish oppression settle as border guards in Slavonia and southern Hungary.

The Austrian Militärgrenze, or “Military Frontier,” thus takes the momentous step of introducing Orthodox Serbs into Catholic Croatian and Hungarian territory.

As the Turkish threat wanes, Croatian nobles demand reincorporation of the military border into Croatia.

Austria, which uses the guards as an inexpensive standing military force, rejects these demands, and the guards themselves oppose abrogation of their special privileges.

The ethnic composition of Hungary has changed dramatically over the past two centuries.

The most purely Magyar areas had been heavily depopulated during the Turkish wars.

These losses had been accompanied by mass immigrations of Serbs, Croats, and Romanians from the Balkans and later by the introduction by the Austrian government of large numbers of German and other colonists.

The Magyars number only some thirty-five percent of the total population by 1720.