Question: when did the crucifix become the symbol of christianity
[{'answer': '4th century', 'provenance': [{'wikipedia_id': '27484195', 'title': 'Christian cross', 'start_paragraph_id': 7, 'start_character': 493, 'end_paragraph_id': 7, 'end_character': 504, 'bleu_score': 1.0, 'section': 'Section::::History.:Early Christian usage.\n'}]}, {'answer': 'the 4th century', 'provenance': [{'wikipedia_id': '27484195', 'title': 'Christian cross', 'start_paragraph_id': 7, 'start_character': 489, 'end_paragraph_id': 7, 'end_character': 504, 'bleu_score': 1.0, 'section': 'Section::::History.:Early Christian usage.\n'}]}, {'answer': 'in the 2nd century', 'provenance': [{'wikipedia_id': '27484195', 'title': 'Christian cross', 'start_paragraph_id': 8, 'start_character': 65, 'end_paragraph_id': 8, 'end_character': 83, 'bleu_score': 1.0, 'section': 'Section::::History.:Early Christian usage.\n'}]}, {'provenance': [{'wikipedia_id': '27484195', 'title': 'Christian cross', 'start_paragraph_id': 8, 'start_character': 0, 'end_paragraph_id': 8, 'end_character': 1225, 'bleu_score': 0.8522030354345911, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2742535147052224446}, 'section': 'Section::::History.:Early Christian usage.\n'}]}, {'provenance': [{'wikipedia_id': '27484195', 'title': 'Christian cross', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 504, 'bleu_score': 0.741385419374419, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2742535147052224446}, 'section': 'Section::::History.:Early Christian usage.\n'}]}, {'provenance': [{'wikipedia_id': '27484195', 'title': 'Christian cross', 'section': 'Section::::History.:Early Christian usage.\n', 'start_paragraph_id': 8, 'end_paragraph_id': 8, 'meta': {'evidence_span': ['The crucifix, a cross upon which an image of Christ is present, is not known to have been used until the 6th century AD.', 'However, the cross symbol was already associated with Christians in the 2nd century, as is indicated in the anti-Christian arguments cited in the "Octavius" of Minucius Felix, chapters IX and XXIX, written at the end of that century or the beginning of the next, and by the fact that by the early 3rd century the cross had become so closely associated with Christ that Clement of Alexandria, who died between 211 and 216, could without fear of ambiguity use the phrase (the Lord\'s sign) to mean the cross, when he repeated the idea, current as early as the apocryphal Epistle of Barnabas, that the number 318 (in Greek numerals, ΤΙΗ) in was interpreted as a foreshadowing (a "type") of the cross (T, an upright with crossbar, standing for 300) and of Jesus (ΙΗ, the first two letters of his name ΙΗΣΟΥΣ, standing for 18). His contemporary Tertullian rejected the accusation of Christians being "adorers of the gibbet" ("crucis religiosi"). In his book "De Corona", written in 204, Tertullian tells how it was already a tradition for Christians to trace repeatedly on their foreheads the sign of the cross. The crucifix, a cross upon which an image of Christ is present, is not known to have been used until the 6th century AD.', 'However, the cross symbol was already associated with Christians in the 2nd century,']}}]}, {'provenance': [{'wikipedia_id': '25245841', 'title': 'Crucifixion in the arts', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['The crucifixion of Jesus has been depicted in religious art since the 4th century CE.', 'Crucifixions and crucifixes have appeared in the arts and popular culture from before the era of the pagan Roman Empire. The crucifixion of Jesus has been depicted in religious art since the 4th century CE. In more modern times, crucifixion has appeared in film and television as well as in fine art, and depictions of other historical crucifixions have appeared as well as the crucifixion of Christ. Modern art and culture have also seen the rise of images of crucifixion being used to make statements unconnected with Christian iconography, or even just used for shock value.', 'The crucifixion of Jesus has been depicted in religious art since the 4th century CE.']}}]}]