apostolicity

noun

1. (uncountable, usually)The quality of being apostolic, notably of preserving authenticity within the mission and tradition of the Christian church as founded by Jesus Christ and his twelve original Apostles, through their representatives and successors in the papacy and episcopate.

   “his Church did its best to trump Rome in apostolicity by declaring that it had been founded by the first-recruited among Christ's Apostles, Andrew.”