Between Ottoman Europe and that other Europe, which saw itself as the only true one (Europe identified itself with Christendom), a line was drawn. It shifted with the Turks’ advance, just as, at the end of the modern period, it would follow their first retreats. When the Ottoman Empire had reached its maximum extension, that line (or rather, that buffer zone) cut diagonally across the European continent, from roughly the Caspian Sea to the Adriatic. To the east, it ran through the northern steppes of the Black Sea, moving northwest of that sea toward central Europe, following the southern edges of Lithuania and Poland. It then crossed northern Hungary and returned south through Croatia. Farther to the west, opposite the western basin of the Mediterranean Sea, that “sea of fear”—in the striking expression of the Italian historian Giuseppe Bonaffini—marked the separation between the “Land of the Franks” and the Maghreb of the Barbary regencies. The eastern basin, on the contrary, where the Ottoman possessions and the scattered fragments of Venetian Romania overlapped a great deal, became an “Ottoman lake,” as these fragments were eliminated one after another.

In a Europe that also included many other cleavages of all kinds, that split became the major border, often compared to the “iron curtain” following World War II. It was a political border separating a single state, that of the “well-guarded countries of Islam”—which also extended over a part of Africa and Asia—from several distinct Christian states. But it was much more than that: it was perceived on both sides as separating two worlds that stood opposed by their religions and more broadly, by their irreducibly different civilizations. That, at least, was the view arising from the respective ideologies previously described. On the Christian side, the Polish and Hungarian borders were so many ramparts or fortifications of Christendom. On the other side, three border fortresses were designated “Sedd-i islm” (barricade of Islam): one in Herzegovina; one in the sanjak of Qirqa near Zemn; and one in the sanjak of Vidin. A fourth, also in the sanjak of Vidin, present-day Kladovo, was called “Feth-i islm” (Conquest of Islam). Belgrade was given the nickname “Dr ül-Jihd.”

Simultaneously, a mysticism of the border (serhdd) developed among the Ottomans, sustained by the holy orders of dervishes. It made reference to the early glory days of Islam at war and gave rise, in the most prosaic everyday life, to holy figures in touch with the afterlife and endowed with supernatural powers. We therefore read in the vita of Sheikh Muslihuddn of Smreska, a spiritual master of the border: “In his time, on all sides the governors and sovereigns acted with his support and, in confrontations with the enemy as in the expeditions of gzis, in his presence and in his absence, they appealed to the departed one for help.” One day, that sheikh was seen in the company of a man who looked like an irregular soldier (a levend), with whom he conversed on familiar terms. When the stranger left, the sheikh asked one of his dervishes: “Have you seen the levend? He is of the Seven.” Referring to the mystic doctrine of Ibn ‘Arab, the biographer explains: “He meant by that that the sheikh was in the position of a pole (kutb), and that he knew the hidden saints (rijl) who were beneath him. But God is the most knowing!”

The symbols used to represent the two opposing sacralized worlds after the conclusion of peace treaties, when mixed commissions sought jointly to realize on the ground the line that separated them, were of the same register. In Dalmatia, crosses carved on tree trunks or on walls of rock delimited Venetian territory, crescent moons that of the Ottomans Similarly, during the Polish-Ottoman demarcation in 1680, four years after the truce of urawno between the two countries, stone mounds were erected on either side to mark the border. On the top of the mounds, the Poles planted crosses, and the Ottomans piled up pieces of wood shaped like turbans. A soldier in the escort of the Polish commissars reported: “When it came time to build mounds, the Turks, using spades they had attached to their saddles, built in a flash a mound of earth, after digging around a large trunk of an oak tree found in the middle. Once the work was completed, their superiors climbed on top of the mound and barked like dogs, their faces turned to the sky, thanking God for having conquered all that by their swords.”

That strong symbolic investment did not prevent the Islamic-Christian border from being, in actual fact, a border like any other in many respects, with the ambiguities common to border situations. A border is both a separation and a passageway, whether official or secret. It can institute an artificial break between ethnically and even religiously similar populations (for example, the Serbs and the Croats on either side of the Ottoman-Hungarian border), or those who, in any event, share a way of life. A border therefore makes no sense for transhumant shepherds or for fishermen in quest of waters full of fish. At the same time, in contrast to “the interior,” it is a place of constant tensions, of “border incidents,” and of contacts and exchanges of all natures.

That Islamic-Christian border, imposed by events, was fundamentally a scandal for both parties. Each saw it as the stigma of an unacceptable situation. For the Christians, it was the mark of an illegitimate presence that had amputated part of their continent, the painful materialization of a historical anomaly. For the Ottomans, the border signified the nonfulfillment of their mission. So long as it survived, it reminded them of their failure; it stood as a reproach. The fact is, it took them a long time to admit openly the reality of their borders. Only a painful learning process would persuade them that they did not rule over a virtually universal empire but over a particular state, which, like other states, had its limits. The preamble to a border demarcation act (sinurnme) with Poland in 1680, inserted in the census registry of the Ottoman province of Podolia, took care to recall, in very stereotypical terms in fact, that though the document that followed had to do with borders, these were not to be taken too seriously, since only God entrusts kingdoms to the rulers of the world here below. A Hadith is evoked promising that, sooner or later, all the territories of unbelievers would become accessible to the warriors of Islam. Already, it was observed, the infidels had begun to desert by fleeing their ramparts, their fortresses, and their forts. As other texts on the subject of diplomacy indicated, fixing the borders could follow only from the principle of “dissimulation” (mudara). It was not until the late eighteenth century—1772 to be exact—that, drawing the lessons from the dramatic setbacks suffered at the hands of Russia, an Ottoman diplomat, Ahmed Resmi, ventured to send a “council treaty” (layiha) to Muhsinzde, grand vizier of the time, expressly recommending that the empire be maintained within the defined borders and condemning dreams of excessive expansion.


Rejected by both parties on principle, the Islamic-Christian border was a militarized border or, to borrow the expression that would be used for the Habsburg border after the Treaty of Karlowitz, a “military border” (Militärgrenze). It was not a continuous rampart over the entire length of the border, a “Great Wall of China”; rather, more complex defense systems appeared on several key segments of it. These were a combination of major fortresses several lines deep, built of stone, and following whenever possible the most modern principles of military architecture (the trace italienne, or bastioned fortress), and of a whole set of forts and guard posts possessing more rudimentary and much less burdensome alert systems. Such was the case for the stockades (palanques; the word, like the object itself, existed on both sides of the Hungarian border): forts surrounded by a defensive wall made of tree trunks into which loopholes had been cut, encircled by a moat. Such structures existed on the Ottoman as well as the Christian side, sometimes separated by very large distances, as in the steppes of the Black Sea. In both cases, depending on the circumstances, they could have an offensive as well as a defensive role: they were used as a base for launching occasional harassment raids in the Kleinkrieg but also for operations of greater scope in times of declared war. The border was never inert, even when, officially, it was peacetime. The very existence of a permanent military presence meant that local incidents would invariably break out in one place or another. In 1567, for example, Emperor Maximilian was moving toward peace with the Turks, yet he nevertheless wrote to one of his officers, captain of the fortress of Kiskomáron, south of Lake Balaton: “Keep your soldiers at the ready as if there were no peace at all.”


In the center of Europe, the need to build a barrier against the Ottoman advance emerged in the fourteenth and fifteenth centuries. Sigismund of Luxemburg, king of Hungary, set in place a system whose cornerstone was Belgrade (Nándorfehérvár), ceded by George Brankovi, the despot of Serbia. One of his successors, King Matthias Corvinus (1458–1490), reorganized that old defense system to make it more coherent and unified. It was now divided into three sectors: to the west, the sector of Croatia-Dalmatia and Slavonia, placed under the authority of a single commander, or ban; in the center, a second sector called Lower Danube, under the authority of the “captain general of the lower regions of the kingdom of Hungary”; and finally, to the east, a third unit of defense under the authority of the voivode of Transylvania. Farther back from the border, the system was complemented by two other parallel fortress systems.

The conquest of Belgrade by Sleyman the Magnificent in 1521 dealt a fatal blow to that system. A few decades later, Ogier Ghiselin de Busbecq, Ferdinand of Habsburg’s ambassador, would draw a military lesson from that event, which he judged key: “It is clear that this event threw open the flood-gates and admitted the tide of troubles in which Hungary is now engulfed. Its first approach involved the death of King Louis, the capture of Buda, the enslavement of Transylvania, the overthrow of a flourishing kingdom, and an alarm among neighboring nations lest the same fate should befall them also.” And he concluded: “These events ought to be a lesson to the princes of Christendom and make them realize that, if they wish to be safe, they cannot be too careful in securing their fortifications and strongholds against the enemy.” But in the wake of 1521, it appeared that the kingdom of Hungary, threatened by such an adversary, did not have the means to assure its own defense. In a sense, Hungary had to “internationalize” it. The young king, Louis II Jagellon, appealed for the support of one more powerful than he, his brother-in-law and ally, Ferdinand of Habsburg, Charles V’s younger brother. Ferdinand was archduke of Austria, and, after Louis II’s accidental death, he would become king of Hungary and Bohemia. During the siege of Belgrade, he sent thousands of Germanic foot soldiers from the hereditary possessions of the Habsburgs to rescue the city. The Ottomans were victorious. In 1522, King Louis II granted Peter Berislavic, ban of Croatia (Croatia had been associated with Hungary by a personal union since 1102), permission to entrust the defense of the Croatian border to Ferdinand, which made Habsburg a de facto suzerain of Croatia. Subsequently, on January 1, 1527, following on the Battle of Mohács, Ferdinand was elected king of Croatia, in exchange for the pledge to defend the country against the Turks. So began the organization of the Habsburg border of Croatia, which would serve as a prototype for the very long Habsburg border generally. The line of that Croatian border with the Turks remained almost unaltered until the Treaty of Berlin in 1878, which would change the rules of the game by placing Bosnia-Herzegovina under Austrian administration. As for the Hungarian part of the border, it was first drawn with the tripartition of the kingdom in 1541: the center became an Ottoman province; the east a principality of Transylvania, vassal of the Ottomans; and the north and west a “Royal Hungary” in the hands of the Habsburgs. At that date, the border began east of the Maros and Temes valleys, then followed the northern edge of the Hungarian great plain to the center and southwest of Transdanubia, finally reaching Slavonia. But unlike the Croatian border, the Hungarian border, nibbled away by the Turks, continued to evolve during the rest of the sixteenth and seventeenth centuries. At the same time, the Habsburgs came to emphasize the Christian and therefore transnational character of the enormous border, which they defended over hundreds of kilometers, from the Carpathians to the Adriatic. In particular, the needs of a centralized organization impelled them to “denationalize” or “exterritorialize,” and also to Germanize, the corresponding zones. German subsidies, obtained with some difficulty from the diets of the Reich, in large part financed that system. It was therefore not only the populations directly threatened or actually affected by the Turkish peril but others as well, across Mitteleuropa as a whole, who assumed the tax burden. The argument given to those for whom the peril was more remote tended to be more religious than national.

The agricultural zones entrusted to settlers behind the lines of fortresses, as well as the fortresses themselves, now escaped the influence of the magnates and traditional institutions, both Croatian and Hungarian. The Habsburgs placed them under Austrian military authority, which, as of 1556, took the form of the Wiener Hofkriegsrat, or Consilium Bellicum. That war council, established in Vienna, assumed the centralized command and military administration of the Turkish border, and also oversaw diplomatic relations with Istanbul. A bureau of experts and an administration, which developed over time and split into specialized bureaus, aided the council. Prince Eugene of Savoy, champion of the fight against the Turks in the late seventeenth and early eighteenth centuries (his martial statue would later be erected in front of the Habsburg Palace on Castle Hill), was war council president from 1703 to 1736. As of 1578, there was also a War Council of Inner Austria (Inner-Österreichischer Hofkriegsrat), established in Gratz until 1705, which controlled the border of Croatia and Slavonia.

The Hungarian and Croatian troops were not sufficient to cover the border, and the Habsburgs, like the authorities in charge of the other segments of the border with the Turks, and like the Turks themselves, were obliged to use every means at their disposal. As Sigismund of Luxemburg had done in his time, they used Orthodox Serbian settlers (Soldatenbauer) and many kinds of religious dissidents. Those attending the large military conference held in Vienna in 1577 even planned to establish the Teutonic Order in Hungary, which seemed logical, since that order, created in the Holy Land during the Crusades, had been installed in Prussia in the thirteenth century to fight the pagan Slavs. They never realized that plan, but they did establish German mercenaries alongside other elements in the Hungarian fortresses. That presence elicited the sharpest of criticisms from the diets of Hungary, which considered the Germans even more barbarous than the Turks. The crimes and impieties they attributed to them reached the level of atrocities. The “remonstrances” (gravamina) of the Diet of 1662 portrayed these German mercenaries as follows: “Against the peasants they have perpetrated homicide, torture, rape, even murder following rape, such that they have committed worse violence than the Turks. They have not even respected the sacred character of the churches but have acted out their guilty passions on prepubescent minors who took refuge in these churches; they even went so far as to cut children to pieces and threw others into the fire.” If these words are not merely an expression of xenophobia and the violence actually went that far—if, that is, some chose the churches to indulge in their abominations—we must believe that undesirables could be found on the ramparts of Christendom!