To this day in the Eucharistic liturgy the priest places nine pieces of bread on the paten used in the liturgy to represent the whole range of the saints: John the Baptist, the prophets of the Old Testament, the apostles, the holy hierarchs, martyrs, ascetics, unmercenary healers (i.e. the saints who were doctors, like Cosmas and Damien, who never charged money to heal), the ancestors of Christ, and the saint whose feast is commemorated on that day.
In the first millennium, saints were recognized as such by an informal method which developed from the ground up: the growth of a cult through popular veneration; the creation of a tradition of icons and legenda; the evidence of miracles; and liturgical recognition in churches and monasteries. The earliest evidence that we have of formal canonization (Greek: anagnorisis, “recognition”) occurs only in the thirteenth century when canonizations were done by decree of the Holy Synod and the Patriarch of Constantinople. This more bureaucratic process, accompanied by a demand for evidence of the miraculous, may well have developed as a result of renewed contacts (not always happy contacts) between Constantinople and the church of the West.
A fourteenth-century text does not disapprove of local liturgical celebration (for example, in the monasteries of Mount Athos), but such a saint would not be celebrated in the Great Church of Hagia Sophia, the seat of the Patriarch, except by synodal decree. The Byzantine East, then, had (and still has) a bit more flexibility than the Western church since it both recognizes the legitimacy of local observation and canonization by synodal decree. This practice is also observed in the Russian Church. In contrast to the Western tendency to canonize many saints, the Orthodox East has been more parsimonious in its willingness to expand the list of canonized saints. When such saints are so “recognized” it typically happens through synodal decree.
It should be noted in passing that the Western church had, in the past, allowed a certain regional autonomy in the matter of the saints even after the canonization process was centralized in Rome. For example, Saint Rita of Cascia (died 1457), the Augustinian visionary ascetic and bearer of the stigmata, enjoyed a fervent cult in her native area where she was buried in an ornate tomb, with accompanying letters from the local bishop lauding her sanctity and permitting prayers in her honor. It was only in 1900, however, that she was formally canonized in Rome (she had been beatified in 1626 after a flurry of reports about miracles through her intercession). Her body was transferred to a new basilica built in her honor in 1946 where her remains are visited by devout pilgrims. Her case is not absolutely singular.
Apart from the vast literature of lives of the saints produced over the centuries, we can mention some “standard” works on the saints used in the Byzantine world which are connected to the liturgical celebrations honoring the saints. These can be briefly described. The Menaion contains hymns and prayers for the celebrations of the feast days of the saints. The Menologion is a collection of the lives of the saints and, in some cases, selected homilies honoring the saint, organized for each month of the year. The entries for a given saint may be read at the liturgy in addition to the prayers found in the Menaion. The Synaxarion is a compilation of brief notices of saints and where they are honored, as well as the details of their martyrdom. Often these notices were incorporated into the Menaion. The Synaxarion is quite similar to the Roman martyrology which, constantly updated, lists by day and month all the saints venerated in the Roman Catholic Church.