Today, the title First Blast of the Trumpet against the monstrous regiment of women evokes images of an approaching army of terrifying woman-like creatures. Its author, John Knox, meant something quite different. It was the title of a short treatise on government (regiment = rule) held by women, a concept he found unnatural (monstrous).
It was not a controversial idea. At that time, most people believed that government was a male prerogative. The biblical examples of women leaders were seen as an indication of the corruption of times when no man could rise to the task.