Although tasawwuf may have been the strongest influence on the beliefs of many, if not most, Ottoman Muslims and permeated Ottoman literature, music, and visual art, it was the Islam of the ulema that was significant in determining the structures of the empire. A few surviving literary fragments suggest that in the fourteenth century, the level of Islamic learning in the Ottoman Empire was very low. Persons wishing for an advanced Islamic education at this period traveled to the old Islamic world, especially to Damascus or Cairo, and it was largely these returning scholars who transferred Islamic doctrine and law to the Ottoman realms and trained the early generations of Ottoman ulema. By the mid-fifteenth century, with the establishment of a system of colleges within the empire and the formation of a learned class, there was no further need for such learning journeys.

The religious colleges (madrasas) attached to mosques throughout the empire, established on the model of the madrasas in the old Islamic world, were the institutions that trained the ulema. The most prestigious colleges were royal foundations, with the Eight Colleges of Mehmed II (1451–1481) and the colleges attached to the mosque of Suleiman I (1520–1566), completed in 1557, enjoying the highest rank, and the foundations of senior statesmen occupying the second tier. Each college was an independent institution with a separate endowment. In the sixteenth century, however, Suleiman I and later Mehmed III (1595–1603) made efforts to formalize the hierarchy of colleges and, to a degree, to control the curriculum, which remained firmly based on the medieval Islamic classics. By the seventeenth century there seems to have been a well-recognized hierarchy, based on the wealth of the endowment and the level of the curriculum. From the late seventeenth century, when the empire began to lose territories, some colleges suffered as the lands that provided their endowments passed into foreign hands.
It was the colleges that maintained the level of Islamic learning in the empire.

A graduate might find a position as imam in an important mosque; he might stay in the system as a teacher (mudarris); or he might choose a career as a judge (qadi). However, if he opted for a legal career immediately on graduating, he would, at least between the sixteenth and eighteenth centuries, find his career confined to the judgeships of small towns. Judgeships of the great cities, especially of Istanbul, Edirne, and Bursa, were reserved for mudarris es from the Eight Colleges or other high-ranking madrasas. Furthermore, between the sixteenth and the eighteenth centuries, a few ulema families monopolized these prestigious teaching positions and judgeships. It was also from the judges of the great cities that the sultan chose the two military judges (kadiasker s), the senior judges of the empire, who sat on the Imperial Council. Below the level of the great cities, however, most of the judges and religious officials tended to be local men, who from the sixteenth century would normally have received part of their education in Istanbul.

The judges, at all levels, administered Islamic law, and in continuing to exercise this function at all times, including times of crisis, they played the major role in ensuring the stability and continuity of Ottoman government. Of the four schools of law within Sunni Islam—the Shafi˓i, Maliki, Hanbali, and Hanafi—the Ottomans adopted the Hanafi school, presumably because this is the school that was already established in pre-Ottoman Anatolia. As the Hanafi jurists typically offer more than one acceptable solution to each legal problem, the Hanafi was perhaps the most flexible of the schools and, for this reason, the most suitable to form the basis of a working legal system. After their formative period in the early Islamic centuries, the four schools remained mutually exclusive. According to Hanafi theorists, for example, a person could have recourse to a Shafi˓i judge only in the two cases for which the Hanafi school offered no solution: the dissolution of an oath or when a deserted wife seeks a dissolution of marriage. The Ottomans endorsed this exclusivity, although among the general population in the Arab lands there was some movement between schools.
Judges in the Ottoman Empire as elsewhere put the law into effect by virtue of the delegation to them of sultanic power. Above the judges stood the muftis. A mufti is a religious authority with the competence to issue fatwa s, authoritative opinions on any religious-legal problems that questioners may ask. A fatwa is not an executive command: it requires a judge's or sovereign's decree to put it into effect. It also differs from a judge's decree, in that the judge's decree is valid only for the case in hand, while the fatwa has a universal validity. Ottoman fatwa s reflect this understanding by reformulating each question so as to conceal the identity of the questioner, even if the questioner was the sultan himself, to remove specific details of the case such as time, locality, or personal identities, and to eliminate details not relevant to the case in question. Between the sixteenth and eighteenth centuries, Ottoman fatwa s in their content, format, and anonymity came increasingly to resemble the classical juristic texts which were the source of their authority.

The mufti in theory remained above and apart from the secular power, a concept embodied from the sixteenth century in Ottoman ceremonial, where the sultan stands in the presence of the chief mufti. His authority derived from his role as interpreter of the Holy Law in its application to mundane realities, including the realities of political power. In much of the Islamic world, muftis acquired their role through public recognition rather than official appointment, and really did stand apart from the secular power. In the Ottoman Empire, however, the muftis were effectively part of the government. The chief mufti, or sheikh al-islamas he came to be known by the seventeenth century, was the senior figure in the religious-legal establishment, and usually achieved the position by serving first as a senior judge and then as a military judge; like these offices, the chief muftiship after the mid-sixteenth century came to be the preserve of a very few ulema families. The chief mufti owed his exalted position partly to the Islamic view that accorded greater dignity to muftis than to judges, but also to the prestige of two sixteenth-century holders of the office, Kemal Pashazade (1525–1534) and Ebu˒s-su˓ud Mehmed (1545–1574). Ebu˒s-su˓ud in particular systematized the chief mufti's major function of issuing fatwa s, ensuring that his office was able to undertake a great volume of work to a high standard. The system that he established remained in its essentials intact until the end of the empire. The chief mufti came to have an important, if informal, role in the Ottoman government. Outside the capital, muftis were sometimes official appointees, but did not enjoy high status of the chief mufti, and their function could often be fulfilled by the mudarris of a local college.

TASAWWUF IN THE OTTOMAN EMPIRE
By the time of the establishment of the Ottoman Empire, tasawwuf was well established in the Islamic world and accepted, within limits, as a form of orthodox Islam. Groups of Sufis had established and continued to establish their own orders (tariqa s) throughout the Islamic world, each with its own saints and distinctive beliefs and rituals. Many of the orders that originated outside the empire found disciples in Ottoman territories. For example, the Khalveti order, named after the eponymous saint ˓Umar al-Khalwati, originated in late-fourteenth-century Azerbaijan. During the fifteenth century the disciples of the Khalveti sheikh Yahya al-Shirvani (d. c. 1463) brought the order to Anatolia. When he was governor of Amasya, the future sultan Bayezid II (1480–1512) was initiated as a Khalveti and established the order in Istanbul after he became sultan. Later, Murad III (1574–1595) was also initiated. Other orders originated within the Ottoman Empire itself. For example, the Bayrami order was the creation of Hajji Bayram (d. 1429/30), who established the fraternity originally among the craftsmen of Ankara. His successor Ak Shemseddin (d. 1459) became a spiritual mentor to Mehmed II.

Once established, Sufi orders sometimes split into smaller groups, the Khalvetis, for example, giving birth to ten or more subgroups during the sixteenth and seventeenth centuries. The Bayramis, too, split into two groups after 1450, the orthodox group following Ak Shemseddin, the "heretical" group, the Melamis, coming under the leadership of ˓Ömer the Cutler (d. 1475/6). This group became particularly active in Bosnia. By the late seventeenth century, however, the Melamis had reemerged as an orthodox order, although distinct from the original Bayramis. Conversely, different groups could merge. The Bektashi order, which took its name from a fourteenth century saint, Hajji Bektash, formed as a coherent order under the leadership of Balim Sultan about 1500, and absorbed and syncretized a wide range of Sufi and other popular beliefs. The Bektashis became particularly well established in Albania.

Many Muslims in the Ottoman Empire belonged to a Sufi order, giving these an essential role not only in disseminating popular faith but also in establishing networks and social solidarity among members. In some orders membership included women, giving them a role not available in orthodox Islam. The orders could also acquire charitable functions, the rural lodges of the Bektashis, for example, providing accommodation for travelers. Above all, they influenced the cultural life of the empire. Each order had its own liturgy and ceremonies, usually involving music, recitation, singing, and sometimes dancing, and to preserve their traditions the orders had to train adepts in these arts, many of whom acquired fame beyond the confines of the organization. The Mevlevi order—the socalled whirling dervishes—had a particular educational role. The sacred text of the order, the lengthy mystical poem known as the Mesnevi, by its eponymous saint, Mevlana Celaleddin Rumi (d. 1273), is written in Persian, a language that Mevlevis therefore had to learn. Since Persian was not taught in Ottoman madrasas, it was above all the Mevlevi lodges that provided instruction and were instrumental in maintaining the enormous prestige of Persian culture in the Ottoman Empire. They also acted as musical and literary academies. The most celebrated Ottoman composers and many Ottoman poets from the seventeenth to the nineteenth century were Mevlevis. While the Mevlevi order was a repository of Ottoman high culture, the Bektashis played a similar role in transmitting popular culture, for example in preserving and adding to the corpus of Turkish religious poetry attributed to the semi-mythical Sufi of the thirteenth or fourteenth century, Yunus Emre.

ORTHODOXY AND HETERODOXY
Although tasawwuf had an intellectual tradition and a structure of "knowledge" that imitated ˓ilm, its primary appeal was aesthetic rather than intellectual. The liturgies of the orders, which aimed to produce a state of ecstasy in participants as they "became drunk with the wine of God's love," offered a religious and theatrical experience that was not available in the impressive but austere ceremonies in the mosques. What was equally important is that the orders, and particularly those with a popular following, institutionalized popular piety, with its appetite for saints and miracles. The hagiographies of Sufi saints, such as Enisi's early sixteenth-century vita of the Bayrami Ak Shemseddin, formed a branch of popular literature that provided entertainment, edification, and a focal point for people's loyalties as adherents to a particular Sufi order. At the same time the shrines of saints, whether or not they had an association with a particular order, became sites of pilgrimage, offering cures for diseases or other of life's problems. It was at this level that beliefs of Ottoman Muslims and Christians often became indistinguishable, with formerly Christian shrines, such as the Sufi lodge at Seyyid Gazi in Anatolia, becoming sites of Muslim veneration. Other sites attracted both Muslim and Christian pilgrims. An example of this was the shrine of St. George on the island of Levitha near Patmos, which became a site of Greek Orthodox, Catholic, and Muslim pilgrimages, St. George also acquiring the Turkish name Koç Baba.

Popular practices, notably visiting saints' tombs and the liturgical use of music and dancing, always aroused the opposition of a section of the ulema. Hostility to these practices became particularly intense in mid-seventeenth-century Istanbul, when Mehmed Kadizade (d. 1635) and his followers, disciples of the fundamentalist scholar Mehmed of Birgi (d. 1575), preached against them in public, attacking in particular the rituals of the Khalvetis. Such attacks, however, never had a lasting effect, and most of the many fatwa s issued on the subject of the Sufi orders are in fact tolerant of their practices, the higher ulema on the whole espousing a latitudinarian understanding of Islam. The affiliation of several sultans and many members of the political elite with the orders ensured that, in general, they enjoyed political protection. Furthermore, popular belief was ineradicable, and permeated even the sultan's palace. As examples of this, the sultans provided employment for makers of talismans, and in 1640, the advice writer Kochi Bey urged the new sultan Ibrahim I (1640–1648) to carefully preserve a loaf of bread whose grain revealed the name Allah.
Nonetheless, despite the latitude of tolerated belief and practice, an official definition of heresy did emerge and became a matter of concern especially during the sixteenth century. This development was closely linked to the claims of the Ottoman dynasty, which drew on Islamic themes to legitimize its rule. Until about 1500, these legitimizing elements came primarily from folk religion. Through dreams, God had promised sovereignty to the first sultan Osman and his father; the dynasty had gained a spiritual descent from Osman's marriage to the daughter of a saint; saints led the sultan's warriors in battle. In the sixteenth century, however, the dynasty came to derive its legitimacy from orthodox Islamic tradition.

This was partly a consequence of the increasing influence of classically trained ulema in the empire, but partly also a consequence of external events. In 1516/17, the conquest of the Mamluk empire made Selim I (1512–1520) and his successors lords of Mecca and Medina, the holy cities of Islam. This gave the Ottoman sultan the prestigious title of "Servitor of the Two Holy Places," and also the responsibility for the safety of the pilgrimage routes to Mecca. He could now, as the upholder of the religion, claim primacy among Islamic sovereigns. At the same time, the rise to power in Iran of the Safavid dynasty, which claimed spiritual power as leaders of the Safavid Sufi order, and whose Shi˓ism contrasted with the Sunnism of the Ottomans, presented a religious and political threat to the Ottoman Empire, especially since the Safavids found many adherents to their order among the sultan's subjects in Anatolia. The Ottomans countered Safavid propaganda by declaring the Safavids and their followers to be worse than infidels, and by presenting the Ottoman dynasty as the only defenders of Sunni Islam against this mortal danger. By the mid-century, Suleiman I was declaring himself to be "the one who makes smooth the path for the precepts of the shari˓a" and the one "who makes manifest the Exalted Word of God" and who "expounds the signs of the luminous shari˓a. " He was also the first Ottoman sultan to assume the title of caliph, implying the leadership of the entire Islamic world. With these developments the dynasty identified itself so closely with orthodox Sunni Islam that disloyalty to one implied disloyalty to the other.
It was particularly during Suleiman's reign, and partly as a result of his claim to be the defender of the faith, that heresy acquired a clear definition.

In identifying heresy, the ulema were not concerned with a person's inner belief or private actions. These are matters between the individual and God. Their concern was with stated belief, certain tenets of the Holy Law or Sunni dogma providing the test. If, for example, a Sufi declared that the ceremonies of his order constituted an act of worship (˓ibada), a term which in the shari˓a refers only to the obligatory purification, prayer, fasting, and alms-giving, then he was a heretic, because in claiming the ceremonies to be "obligatory" he was claiming an authority in prescribing ritual that only the shari˓a possessed. It was this test that the sultan used to execute the Melami Oğlan Şeyh and his followers in 1528. Provided, however, the Sufi did not declare his practices to be an act of worship, he remained within the bounds of orthodoxy. Since the shari˓a forbids Muslims to drink wine, if a Muslim declares wine to be licit, he has abjured the shari˓a, and become liable to death. If, however, he drinks wine without believing it to be licit he is not a heretic.

In Ottoman religious "trials" the key to identifying heresy was the accused's statements on what is canonically forbidden, permitted, and obligatory. A heretic was someone whose stated beliefs did not conform with the shari˓a. However, in the more merciless pursuit of Safavid sympathizers within the Ottoman realms a key indicator was whether or not the accused cursed the Orthodox caliphs, the denunciation of the first three successors to the prophet Muhammad being a tenet in Shi˓ite belief. Public behavior could also indicate heresy. It was for this reason that Suleiman I decreed in 1537 that the authorities should build mosques in all villages that lacked one and note who failed to attend the obligatory congregational prayers. In this way the sultan not only enforced Sunni ritual, in his capacity as protector of the faith, but could also, by their refusal to perform obligatory prayers, identify heretics. Since by this time the sultan identified his own legitimacy with Sunni orthodoxy, disavowal of the commands of the shari˓awas also identified as an act of rebellion against the dynasty.

In practice, therefore, the definition of heresy served to identify political opponents of the dynasty, and with changing political circumstances certain heretical beliefs became more acceptable. The persecution of Ottoman Shi˓ites, for example, seems to have stopped when, from the mid-seventeenth century, the Safavids of Iran no longer presented a political and ideological danger. Furthermore, since the Ottoman government demanded of Muslims no more than verbal adherence to certain tenets of the shari˓a and the outward performance of its obligatory rituals, and did not examine inward faith, a huge variety of beliefs and practices were able to flourish unmolested within Ottoman Islam.