Oh how wrong? In being 'mistaken,' such as you say, Catholics finds themselves in the company of the saints and doctors of the Church. This was true since the ascension till today, and through all the tomorrows.
St. Jerome wrote a rebuke to Vigilantius asking who had started to spread heretical views. In part of the rebuke we see the following discussion of praying to the saints:
If the Apostles and Martyrs, while still in the body, can pray for others, at a time when they must still be anxious for themselves, how much more after their crowns, victories, and triumphs are won! One man, Moses, obtains from God pardon for six hundred thousand men in arms; and Stephen, the imitator of the Lord, and the first martyr in Christ, begs forgiveness for his persecutors; and shall their power be less after having begun to be with Christ? The Apostle Paul declares that two hundred three score and sixteen souls, sailing with him, were freely given him; and, after he is dissolved and has begun to be with Christ, shall he close his lips, and not be able to utter a word in behalf of those who throughout the whole world believed at his preaching of the Gospel? And shall the living dog Vigilantius be better than that dead lion? ("Contra Vigilant.", n. 6, in P.L., XXIII, 344).
CHURCH FATHERS: Against Vigilantius (Jerome)
Saint Augustine of Hippo also discuses praying to the saints:
'There is an ecclesiastical discipline, as the faithful know, when the names of the martyrs are read aloud in that place at the altar of God, where prayer is not offered for them. Prayer, however, is offered for the dead who are remembered. For it is wrong to pray for a martyr, to whose prayers we ought ourselves be commended." Sermon 159, 1
St. Augustine:
" This it was that the blessed martyrs did in their burning love; and if we celebrate their memories in no mere empty form, and, in the banquet whereat they themselves were filled to the full, approach the table of the Lord, we must, as they did, be also ourselves making similar preparations. For on these very grounds we do not commemorate them at that table in the same way, as we do others who now rest in peace, as that we should also pray for them, but rather that they should do so for us, that we may cleave to their footsteps; because they have actually attained that fullness of love, than which, our Lord has told us, there cannot be a greater.." St. Augustine, Tractate 84 (John 15:13)
CHURCH FATHERS: Tractates on the Gospel of John (Augustine)
St. Augustine again:
" Faustus' love of evil-speaking has made him forget his own creed; or perhaps he spoke in his sleep about ghosts, and did not wake up even when he saw his words in writing. It is true that Christians pay religious honor to the memory of the martyrs, both to excite us to imitate them and to obtain a share in their merits, and the assistance of their prayers. (Against Faustus 20, 21)
CHURCH FATHERS: Contra Faustum, Book XX (Augustine)
St. Augustine again:
" For the souls of the pious dead are not separated from the Church, which even now is the kingdom of Christ; otherwise there would be no remembrance made of them at the altar of God in the partaking of the body of Christ, nor would it do any good in danger to run to His baptism, that we might not pass from this life without it; nor to reconciliation, if by penitence or a bad conscience any one may be severed from His body. For why are these things practised, if not because the faithful, even though dead, are His members? Therefore, while these thousand years run on, their souls reign with Him, though not as yet in conjunction with their bodies. And therefore in another part of this same book we read, Blessed are the dead who die in the Lord from henceforth and now, says the Spirit, that they may rest from their labors; for their works do follow them. Revelation 14:13 The Church, then, begins its reign with Christ now in the living and in the dead. For, as the apostle says, Christ died that He might be Lord both of the living and of the dead. Romans 14:9 But he mentioned the souls of the martyrs only, because they who have contended even to death for the truth, themselves principally reign after death; but, taking the part for the whole, we understand the words of all others who belong to the Church, which is the kingdom of Christ. (The City of God 20, 9)
CHURCH FATHERS: City of God, Book XX (St. Augustine)
It wasn't until a certain monk, of the schismatic type, do we find any objection to 'praying to the saints'.
JoeT
