Writing in 1886, Dr. William P. Killen regarded all the Ignatian epistles, beginning with that to the Romans, as having been pseudepigraphically composed in the early 3rd century. His reasons included their episcopal emphasis, which is otherwise unknown before the reign of Callistus, the Bishop of Rome around 220.
Most scholars, however, accept at least the two Ignatian epistles which were referenced by Origen,[15] and believe that by the 5th century, this collection had been enlarged by spurious letters.
The original text of six of the seven authentic letters are found in the Codex Mediceo Laurentianus written in Greek in the 11th century (which also contains the pseudepigraphical letters of the Long Recension, except that to the Philippians),[16] while the letter to the Romans is found in the Codex Colbertinus.[6]
Some of the original letters were, at one point, believed to had been changed with interpolations.
The oldest is known as the "Long Recension" which dates from the latter part of the fourth century.[6] These were created to posthumously enlist Ignatius as an unwitting witness in theological disputes of that age, but that position was vigorously combated by several British and German critics, including the Catholics Denzinger and Hefele, who defended the genuineness of the entire seven epistles.[6]
At the same time, the purported eye-witness account of his martyrdom is also thought to be a forgery from around the same time.
A detailed but spurious account of Ignatius' arrest and his travails and martyrdom is the material of the Martyrium Ignatii which is presented as being an eyewitness account for the church of Antioch, and attributed to Ignatius' companions, Philo of Cilicia, deacon at Tarsus, and Rheus Agathopus, a Syrian.
quotes from Wiki
Additionally, Ignatius didn’t write ANY of his letters in English!