Dear Mike, I don't know about "mixing up" the Isham/Isam/Isom/Isaiahs. I have found one court record in Jennings County,Indiana where two different spellings were used, as well as Isaiah for the same man. One thing I have learned over the years is that there are no spelling absolutes in genealogy. You must be open to accept that everyone didn't have an education and words were frequently spelled the way they sounded. Just as Molly is also called Polly, and Martha and Patsy are the same person, I believe that Isam/Isom and Isham can be interchanged. I just pay attention to the location and the date to sort them out. Pat