An author can petition a distant sovereign by arguing that injustice is being committed by intermediaries without the ruler's knowledge, preserving loyalty to the crown while condemning its agents. This lets a subject denounce an entire administrative apparatus (colonial officials, priests, encomenderos) as corrupt without committing treason, by framing the king as the uninformed potential remedy rather than the source of harm.
Presenting a conquered people's pre-conquest order as already morally governed, with its own laws, justice, and functional administration, reframes conquest as the introduction of disorder rather than its cure. Viewed this way, the colonizers' claim to bring civilization inverts: the colonized held the civilization and the colonizers brought theft, drunkenness, and moral collapse.
Combining drawn images with text lets an author reach audiences who cannot or will not read the argument, and makes claims (abuse, hierarchy, ideal order) legible at a glance that prose would bury. The picture carries the evidentiary and emotional weight while the caption anchors its meaning, so persuasion operates on two channels at once.
Felipe Guaman Poma de Ayala, an Andean nobleman, spent decades producing a roughly 1,200-page illustrated letter to King Philip III of Spain (completed around 1615) cataloguing Inca history and documenting specific abuses by colonial priests, officials, and settlers against indigenous Andeans. The manuscript was never delivered to the king and surfaced only in 1908 in a Copenhagen library, having had no effect on the policies it sought to change.