Ringed cross

The ringed cross is a class of Christian cross symbols featuring a ring or nimbus. The concept exists in many variants and dates to early in the history of Christianity. One variant, the cruciform halo, is a special type of halo placed behind the head of Jesus in Christian art. Other common variants include the Celtic cross, used in the stone high crosses of Ireland and Britain; some forms of the Coptic cross; and ringed crosses from western France and Galicia.

The nimbus or ringed shape was appended to the Christian cross and other symbols relatively early. In these contexts it apparently derived from the earlier Roman garland of victory. The Chi Rho-in-circle motif was widespread in the Roman Empire by the late 4th century, and garlanded and ringed crosses were popular in imperial Ravenna by the 5th century, influencing the later versions. The cruciform halo or cross halo, a halo incorporating a cross, emerged as a distinctive type of halo painted behind the head of members of the Holy Trinity, especially Jesus, and occasionally others. In other cases, the combination of cross and nimbus symbolized the presence of Christ throughout the cosmos, with the nimbus representing the celestial sphere. Notable early examples include the cosmological ringed cross in the 5th-century Mausoleum of Galla Placidia, and the 6th-century Crux Gemmata in the Basilica of Sant'Apollinare in Classe.

...
Wikipedia