▁main ▁church ▁building ▁is ▁one ▁of ▁a ▁hand ful ▁of ▁structures ▁remaining ▁in ▁the ▁city ▁that ▁pre date ▁the ▁ 1 8 7 1 ▁Great ▁Chicago ▁Fire , ▁and ▁is ▁the ▁city ' s ▁oldest ▁standing ▁church ▁building . ▁ ▁History ▁Old ▁St . ▁Patrick ' s ▁Church ▁was ▁founded ▁on ▁E aster ▁Sunday , ▁April ▁ 1 2 , ▁ 1 8 4 6 . ▁The ▁parish ▁was ▁originally ▁hous ed ▁in ▁a ▁wooden ▁building ▁at ▁Rand olph ▁Street ▁and ▁Des P la ines ▁Street . ▁In ▁the ▁ 1 8 5 0 s , ▁the ▁present ▁church ▁building ▁was ▁constructed ▁of ▁yellow ▁C ream ▁City ▁brick ▁from ▁Mil w au kee . ▁Two ▁oct ag onal ▁sp ires , ▁said ▁to ▁represent ▁the ▁Eastern ▁Church ▁and ▁the ▁Western ▁Church , ▁were ▁added ▁in ▁ 1 8 8 5 . ▁By ▁the ▁ 1 8 8 0 s , ▁most ▁of ▁the ▁parish ▁was ▁composed ▁of ▁Irish - Amer icans , ▁and ▁from ▁ 1 9 1 2 ▁through ▁ 1 9 2 2 , ▁the ▁interior ▁was ▁re decor ated ▁by ▁Thomas ▁A . ▁O ' Sh augh ness y ▁and ▁others ▁in ▁the ▁C elt ic ▁Rev ival ▁style . ▁O ' Sh aug ness y ▁mode led ▁some ▁of ▁the ▁orn ament ation ▁after ▁the ▁ill umin ations ▁found ▁in ▁the ▁Book ▁of ▁K ells . ▁The ▁building ▁was ▁added ▁to ▁the ▁National ▁Register ▁of ▁Historic ▁Places ▁in ▁ 1 9 7 7 . ▁ ▁Today , ▁Old ▁St