Ben Jonson's view concerning the place of "Custome" within language reflects the considerable shift in the fortunes of English which had occurred in the century which led up to his (posthumously published) arguments concerning its upkeep. In Timber (1640) he insists that:

"Custome, is the most certaine Mistresse of Language, as the publicke stampe makes the current money. But wee must not be too frequent with the mint, every day coyning... Yet when I name Custome, I understand not the vulgar Custome: For that were a precept no lesse dangerous to Language, then life, if wee should speake or live after the manners of the vulgar: But that I call Custome of speech, which is the consent of the Learned; as Custome of life, which is the consent of the good."
That he also published a work entitled English Grammar... for the Benefit of All Strangers, out of his Observation of the English Language now Spoken, and in Use reminds us that his concern is for his native language and its living properties. The sense of palpable "danger" to what was and remains essentially only a means of communication tells of a concern for the potential intangible consequences (affecting language and life) of the degradation of English. This, and the fact it was felt to be acceptable to discuss the grammar and usage of English in a publication, demonstrates the new interest in the vernacular as a "serious" language, one whose usage informed of both status and morality. Although Chaucer and his contemporaries had done much to elevate the standing of a disparate tongue (composed of numerous distinct regional dialects) between the fourteenth and sixteenth centuries, there was a continuation of the division between French as the language of court, Latin as that of formality and religion, and English as that of the people or the mob depending on one's standing. Only with the reign of Elizabeth I and the desire for national and religious unity after years of political confusion did English achieve some kind of consensus of approval. So we arrive at Jonson's early brand of prescriptivism.