▁the ▁number ▁ 3 1 8 ▁( in ▁Greek ▁numer als , ▁ Τ Ι Η ) ▁in ▁Gen esis ▁ 1 4 : 1 4 ▁was ▁a ▁for esh adow ing ▁( a ▁" type ") ▁of ▁the ▁cross ▁( the ▁letter ▁T au ) ▁and ▁of ▁Jesus ▁( the ▁letters ▁I ota ▁E ta ). ▁Clement ' s ▁contemporary ▁T ert ul li an ▁ ▁reject s ▁the ▁accus ation ▁that ▁Christians ▁are ▁ ▁cru cis ▁religios i ▁( i . e . ▁" ador ers ▁of ▁the ▁g ib bet "), ▁and ▁returns ▁the ▁ ▁accus ation ▁by ▁li ken ing ▁the ▁worship ▁of ▁pag an ▁id ols ▁to ▁the ▁worship ▁of ▁pol es ▁or ▁st akes . ▁ ▁In ▁his ▁book ▁De ▁Cor ona , ▁written ▁in ▁ 2 0 4 , ▁T ert ul li an ▁tells ▁how ▁it ▁was ▁already ▁a ▁tradition ▁for ▁Christians ▁to ▁trace ▁repeatedly ▁on ▁their ▁fore head s ▁the ▁sign ▁of ▁the ▁cross . ▁ ▁While ▁early ▁Christians ▁used ▁the ▁T - shape ▁to ▁represent ▁the ▁cross ▁in ▁writing ▁and ▁gesture , ▁the ▁use ▁of ▁the ▁Greek ▁cross ▁and ▁Latin ▁cross , ▁i . e . ▁cross es ▁with ▁intersect ing ▁be ams , ▁appears ▁in ▁Christian ▁art ▁towards ▁the ▁end ▁of ▁Late ▁Anti qu ity . ▁An ▁early ▁example ▁of ▁the ▁cru c iform ▁h alo , ▁used ▁to ▁identify ▁Christ ▁in ▁paint ings , ▁is ▁found ▁in ▁the ▁Mira cles ▁of ▁the ▁Lo aves ▁and ▁Fish es ▁m osa ic ▁of