TurretinFan recently debated William Albrecht on the subject of the intercession of the saints. Albrecht claimed that none of the church fathers opposed praying to the deceased. He said that he didn't know of anybody who opposed the practice before John Calvin, though he later added the qualifier that Vigilantius opposed it in the fourth century. He cited a passage from Hippolytus, popularized by Ludwig Ott, to argue that Hippolytus supported the practice of praying to the dead. He also claimed that Origen supported it, among many others.
Actually, the evidence suggests that prayer to the dead wasn't practiced by believers in the Biblical era, is sometimes contradicted by the Biblical authors, and was rejected in the earliest generations of patristic Christianity. You can find a collection of many of my posts on these issues here. And here's a listing of our posts under the Prayer label. (Keep clicking "Older Posts" at the bottom right of the screen to see more.)
In a post on Hippolytus here, I explain that he seems to oppose praying to the dead rather than supporting it. I don't know if Albrecht read more of Hippolytus' commentary on Daniel than the one passage he cited. He may have just been repeating what he saw in Ludwig Ott. But Tom Schmidt recently published the first full English translation of Hippolytus' commentary, and I've read the entirety of it. If you read the passage Ott cites in context, it doesn't support the conclusion Ott and Albrecht have used it for. Similarly, the evidence suggests that Origen opposed prayer to the dead rather than supporting it. Celsus, a second-century opponent of Christianity Origen wrote against, suggests that Christians reject prayer to deceased humans, angels, or any other beings other than God, and Origen suggests the same in response. See here and here, among other posts I've written about Celsus and Origen's comments on these issues.
In a thread here you'll find a lengthy comments section in which I address Hermas, Athenagoras, and many other patristic sources. You can use the Ctrl F feature on your keyboard to find the material you're interested in. For example, if you search for "Vigilantius", you'll find my comments on how he wasn't alone in opposing prayers to the dead in the fourth century. Other church leaders and laymen held the same view.
In our index post on prayer, you'll also find links to posts in which we address the Biblical evidence. On the issue of deceased believers being spiritually alive, which supposedly exempts them from Biblical passages about not trying to contact the dead, see here. For example, go to the comments section of that thread, and read my posts at 4:55 A.M. and 4:59 A.M. on 6/4/10. On Revelation 5:8, which was cited by Albrecht, see here. See here concerning catacomb inscriptions. Albrecht made much of the fact that deceased believers in heaven are sometimes portrayed as being aware of events on earth. On that subject, see here. The same post expands on a good point TurretinFan made during the debate, that prayer to the dead is absent in scripture across so many passages and so many contexts addressing so many timeframes.