One of the hard things about being a Reformed Protestant is the fact that one cannot find a Reformed Protestant or a Reformed Protestant Church before the Protestant Reformation. If a Reformed Protestant today were dropped into any period of history before the Reformation, he would be a heretic. At the least it's something to think about.
One of the Catholic ideas Reformed Protestants hate is the concept of the intercession of the saints--the idea that, after death, the saints intercede with God for people still alive on earth and can do us good. (Of course, the "intercession" of the saints is not like the unique intercession of Christ, who alone can satisfy for our sins and merit for us justification. The intercession of the saints in heaven is like the intercession of the saints on earth, as we pray for each other and God helps us in response to the prayers of others. Of course, as St. James says, "the effectual fervent prayer of a righteous man availeth much" [James 5:16], and who is more righteous and close to God than the saints whose souls have been perfected in the presence of God in heaven?) Below is an account of an act of intercession which took place in 205 AD, a little over a hundred years after the end of the Apostolic age. It is recorded by the great Church historian Eusebius, writing in the early 4th century (around the time of the famous Council of Nicaea, which gave us the first part of the Nicene Creed). So here we have a testimony to the doctrine of the intercession of the saints in the Church at the same time she is fighting Arianism and establishing the classic formulas of the historic Nicene Creed.
The text is from Chapter V of Book VI of Eusebius's Ecclesiastical History, and I have taken it from the online plain text version at the Christian Classics Ethereal Library (footnotes removed).
1. Basilides may be counted the seventh of these. He led to martyrdom the celebrated Potamiæna, who is still famous among the people of the country for the many things which she endured for the preservation of her chastity and virginity. For she was blooming in the perfection of her mind and her physical graces. Having suffered much for the faith of Christ, finally after tortures dreadful and terrible to speak of, she with her mother, Marcella, was put to death by fire.
2. They say that the judge, Aquila by name, having inflicted severe tortures upon her entire body, at last threatened to hand her over to the gladiators for bodily abuse. After a little consideration, being asked for her decision, she made a reply which was regarded as impious.
3. Thereupon she received sentence immediately, and Basilides, one of the officers of the army, led her to death. But as the people attempted to annoy and insult her with abusive words, he drove back her insulters, showing her much pity and kindness. And perceiving the man's sympathy for her, she exhorted him to be of good courage, for she would supplicate her Lord for him after her departure, and he would soon receive a reward for the kindness he had shown her.
4. Having said this, she nobly sustained the issue, burning pitch being poured little by little, over various parts of her body, from the sole of her feet to the crown of her head. Such was the conflict endured by this famous maiden.
5. Not long after this Basilides, being asked by his fellow-soldiers to swear for a certain reason, declared that it was not lawful for him to swear at all, for he was a Christian, and he confessed this openly. At first they thought that he was jesting, but when he continued to affirm it, he was led to the judge, and, acknowledging his conviction before him, he was imprisoned. But the brethren in God coming to him and inquiring the reason of this sudden and remarkable resolution, he is reported to have said that Potamiæna, for three days after her martyrdom, stood beside him by night and placed a crown on his head and said that she had besought the Lord for him and had obtained what she asked, and that soon she would take him with her.
6. Thereupon the brethren gave him the seal of the Lord [baptism]; and on the next day, after giving glorious testimony for the Lord, he was beheaded. And many others in Alexandria are recorded to have accepted speedily the word of Christ in those times.
7. For Potamiæna appeared to them in their dreams and exhorted them. But let this suffice in regard to this matter.