In this paper, the author elaborates the subject of the cult of martyrs on east Adriatic coast. The main subject are Christians martyrs who lost their lives during the persecutions of the Christians that occurred during the third stage from 250 to 311 AD. After Diocletian's persecutions in 304, the martyrs were secretly buried in private graveyards in Salona. Over time, these graveyards started to expand to a considerable extent, as everyone wanted to lie close to the saints. Later on great basilicas were built above these burial grounds. Priest Asterius and four Diocletian's soldiers were buried in Kapljuč, which is the oldest of these cemeteries. A big basilica, heavily renovated over time, used to stand at this cemetery. St. Anastasius was buried at Marusinac, which is perhaps the best known site in Salona. Manastirine is however the largest and the best explored cemetery, and Saint Dujam was buried there. The only martyr buried in Poreč is the first known bishop St Maurus. They are depicted all together on mosaic in oratory next to the baptistery of St John Lateran by order of Pope John IV. The first of these earlier churches in Poreč was built in a private house next to the north-eastern city walls at the time when Christianity was still prosecuted, and when St. Maurus was executed in these prosecutions. A double church was then built on the same spot, so as an earlier three naved basilica. Cemeteries in Salona are well preserved while the architecture of domus ecclesiae is damaged by further adaptations.