Brooks Brothers shirts in a catalog from the 1910s. Besides cotton, they sold shirts in silk, silk-linen, and silk-wool. Unlike today, the formal shirt was made of linen.
The famous button-down appears on the lower right of the page, but in white cheviot cotton. Cheviot is listed as a distinct cloth from oxford in Baker's Dictionary of Men's Wear (1908) and the more recent Fairchild Book's Dictionary of Textiles (2013).
Many shirts were worn with stiff, detachable collars. Brooks had a selection of 33 (!) collars. They were narrow spread or wing in design, following the fashion of the 1910s:
The collar measurements:
Brooks carried made-to-measure shirts, with the choice of attached or detachable collars. Linen shirts were much more common than today. Brooks even had boxer shorts made in linen or silk.
While some people equate cotton cheviot and oxford cloth, they are listed as being distinct in the made-to-measure shirt page above.
This page, from outside of the catalog, describes the differences between negligee, dress, work, and outing shirts: