The Four Desert Ascetics
The Orthodox calendar for August 18 commemorates four ascetics who lived in the desert. The Synaxarion states plainly that their names are unknown, and no further biographical detail, location, or date has been preserved.
Later liturgical listings, such as the OrthodoxWiki calendar for August 18, likewise note simply "four holy ascetics" without elaboration. They are remembered for the witness of the desert ascetic life, even though their identities have not survived in the record.
The Three Hundred Saints and the Smashing of Idols
The three hundred saints are recorded as having been burned in a fire for smashing idols. They are also known as the "Holy Host of Paupers," and several sources connect them to the martyrdom of Saints Florus and Laurus.
According to that narrative, after a pagan temple had been constructed, the Christians gathered there, destroyed the statues of the pagan gods, and set up the holy Cross in the eastern section, spending the night in prayer. When the authorities learned what had been done, the regional administrator condemned to burning the former pagan priest Mamertin, his son, and three hundred Christians.
These three hundred are the martyrs commemorated on this day. The synaxarion and calendar listings do not preserve their individual names.
Connection to Florus and Laurus
The fuller account behind the three hundred martyrs is tied to Saints Florus and Laurus, twin stonemasons traditionally placed in the 2nd century. By tradition they were trained in their craft by Christian teachers and were later employed to build a pagan temple in the city of Ulpiana, in the Roman province of Dardania.
During the construction, a chip of stone is said to have injured the eye of the son of a pagan priest named Mamertin; after the brothers healed the boy through prayer and the sign of the Cross, Mamertin and his son converted to Christianity. When the temple was complete, the local Christians gathered there, smashed the idols, and erected a cross.
In response the authorities burned the three hundred Christians, including Mamertin and his son. Florus and Laurus themselves were, by tradition, cast into a dry well and buried alive. These details come from the Florus and Laurus tradition rather than from any independent account of the three hundred, whose own names remain unrecorded.