What do they mean by the word "INVOKE" here?:

"To give legitimacy to their claims of authority, Christians often invoked the apostles. Thus an early affirmation of faith was called the Apostles' Creed, and the ordination lineage of bishops was referred to as apostolic succession.Various nations claimed that their peoples had been converted by the missionary activity of one or another of the apostles..

Question

What do they mean by the word "INVOKE" here?:

"To give legitimacy to their claims of authority, Christians often invoked the apostles. Thus an early affirmation of faith was called the Apostles' Creed, and the ordination lineage of bishops was referred to as apostolic succession.Various nations claimed that their peoples had been converted by the missionary activity of one or another of the apostles..

anonymous · Answer

From an online dictonary:
Definition of INVOKE
transitive verb
1a : to petition for help or support 
b : to appeal to or cite as authority
2: to call forth by incantation : conjure
3: to make an earnest request for : solicit
4: to put into effect or operation : implement
5: bring about, cause 

1b seems like your answer.