The Testamentum, which is Latin for "Testament," was not divided into 'Old' and 'New' testaments like the modern Bible and was dramatically shorter.

The Marcionite Christians determined that the Hebrew Bible, and the deity portrayed within it, are diametrically opposed to the teachings and salvation of Jesus Christ. The proof is self-evident in the form of the scriptures themselves, and that's why it wasn't included in the original Christian Bible.

The Testamentum was divided into two parts, the Gospel of the Lord Jesus Christ (or the Evangelicon), as revealed to Paul the Apostle, and the eleven Epistles of Paul (or Apostolicon). This is the foundational Christian canon to which virtually every denomination can trace its roots.

The Apostolicon consisted of the following epistles: Galatians, 1 Corinthians, 2 Corinthians, Romans, 1 Thessalonians, 2 Thessalonians, Laodiceans (Ephesians), Colossians, Philippians, Philemon, and Alexandrians.

Marcion's canon rejected the entire 46-book 'Old' Testament, along with all other epistles and gospels of what would become the 27-book 'New' Testament canon, which had yet to be compiled during his life.