A martyr's cross is a Christian iconographic element, especially common in Eastern Orthodox iconography, used to indicate that the saint holding it â typically in their right hand â is a martyr.
The martyr's cross first entered Christian iconography during the fifth and sixth centuries, alongside wreaths. Martyrs are not required to be depicted holding one, although it is often the case that they are, especially in the case of lay and new martyrs.
The martyr's cross symbolises the 'burden or suffering endured by martyrs' which 'represent[s] their sacrifice for their faith.'