Language and style Vocabulary, sentence structure, employment of idioms and common phrases, etc. are analyzed for consistency with the author's other known works. A similar style implies common authorship, while a radically divergent vocabulary implies different authors. For example, E. J. Goodspeed argued that the vocabulary of the Epistle to the Ephesians showed a literary relationship with the First Epistle of Clement, written around the end of the 1st century. Similarly, E. Percy argued that the speech and style of Colossians more strongly resembled Pauline authorship than not. Of course, style and language can vary for reasons other than differing authorship, such as the subject of the letter, the recipient, the circumstances of the times, a different amanuensis, or simply maturation on the part of the author. Contents and theology Similar to internal evidence, doctrinal consistency and development are examined against the author's other known works. Theological themes like the eschaton or the Mosaic Law could reappear in different works, but in a similar manner. A consistent point of view implies a common author; contradictory or unrelated teachings imply multiple authors. For example, W. Michaelis saw the Christological likeness between the Pastoral Epistles and some of Paul's undisputed works, and argued in favor of Pauline authorship. A problem with this method is analyzing the coherence of a body of diverse and developing teachings. This is seen in the disagreement between scholars. For example, with the same epistles mentioned above, B. S. Easton argued their theological notions disagreed with other Pauline works, and rejected Pauline authorship. G. Lohfink argued the theology of the Pastoral epistles agreed with Paul's, but took this as proof someone wishing to enjoy the authority of an apostle copied the famous church leader. Undisputed epistles The name "undisputed" epistles represents the scholarly consensus asserting that Paul authored each letter. The undisputed letters are: Romans First Corinthians Second Corinthians Galatians Philippians First Thessalonians Philemon These seven letters are quoted or mentioned by the earliest of sources, and are included in every ancient canon, including that of Marcion (). There is no record of scholarly doubt concerning authorship until the 19th century when, around 1840, German scholar Ferdinand Christian Baur accepted only four of the letters bearing Paul's name as genuine, which he called the Hauptebriefe (Romans, 1 and 2 Corinthians, and Galatians). Hilgenfeld (1875) and H. J. Holtzmann (1885) expanded Baur's four into seven, by adding Philemon, 1