It was not until 1958 that Ammi Phillips's identity as the painter of both groups of portraits was established by Barbara and Larry Holdridge, and endorsed by Mary Black, writing on May 21, 1959, to three fellow folk-art historians, "You are the ones who should be the first to know that I have joined the opposition the Holdridges and now believe that the Border Limner, Ammi Phillips, A. Phillips, and the Kent Limner are one and the same person." Additional works were identified, showing the artist's transition from the delicate coloration of the Border period to the bold and dramatic works that followed. Some paintings that had previously been attributed to John Bradley were also identified as the work of Ammi Phillips. By 1976, there were approximately 400 paintings securely attributed to Phillips, who is now recognized as one of the most prolific American folk painters of his time. Scores more have been discovered since then.