Some argue that classical liberalism (now conservatism), as a philosophy, began in the Enlightenment (late 17th century into the 18th century) with the works of thinkers such as Hobbes, Locke, Smith, Bastiat, and Hume. As Friedrich Hayek categorized it, classical liberalism had a French and British branch.
Conservatism, according to this narrative, was rather a unique and radical idea in comparison to all previous philosophies. In other words, what the English did in the Glorious Revolution was the result of a new Protestant paradigm shift from the old and defunct schools of thought which permeated a still predominantly Catholic Continent.
Usually such a movement in the “Enlightenment” is pitted as rational Protestants in England and the Netherlands, along with more secular French and German thinkers, against the superstitious and ritualistic Catholics from Spain and France. As if such areas were entrenched in some permanent medieval paradigm.
I find such a narrative to be antiquated and lacking in detail or support. The roots of classical liberalism are to be traced (obviously in Judeo-Christian writings, the Bible not being the least) in thought to the works of Aristotle (his Politics) then to Augustine (City of God), to Thomas Aquinas (Summa Theologica), but they were formulated and codified not in the Enlightenment but rather in early 16th-century Spain, with the School of Salamanca.
The School of Salamanca was a group of Jesuit/Dominican thinkers that more or less followed in the Thomist tradition (Scholastics) and their scholarly focus was generally deployed to understanding the various issues in the context that Spain found itself in as an imperial nation in the early 16th century with the unification of the Holy Roman Empire and Spain and its conquests in the New World.
This meant that they dealt with the issue of the humanity of American Indians (do they have souls?), the value of money (all that bullion), the human condition itself (where does sovereignty come from?), the free market (trade across a vast colonial empire), and international law (just wars and treaties).
From the beginning, with the school’s founder Francisco de Vitoria, this group of thinkers more or less made the argument of classical liberalism. They asserted that even the native Americans were humans worthy of dignity. That government’s legitimacy was founded in the will of those under it in a contractual manner, the opposite of the English theory at the time which posited Divine Right (as the king was also head of the Anglican Church).
Free trade was seen as a moral good, as it was the use of free will to the benefit of yourself and your fellow man (thus increasing the bonds of community among all). Value in goods was also subjective (and relied on scarcity), and this meant that only free allocation of goods and services could create efficient outcomes (and was the natural result of said free will).
The concept of usury was undone by the time theory of value posited by Martín de Azpilcueta. The concept of private property being a right of man was posited by Diego de Covarrubias y Leyva, entailing that one had the right to the fruits of that property. These thinkers also devised the concept of just war. To summarize, their theory was that war was supposed to be used to prevent greater evils.
This meant that war ought to occur in order to prevent a greater war, to depose unjust enemies (a government that represses the natural rights of humans), and when it was possible (as a form of charity) to establish some form of peace in areas without structure. In terms of humanity, the school argued that all humans (Christian and non-Christian) had inherent rights that came with our humanity (Vitoria called it ius gentium, the law of all people), and this was the foundation of international law.
In short, such a school formulated classical liberalism (conservatism as we know it today). All humans have an inherent right to life, liberty, and the pursuit of happiness, and the state is supposed to act in a way that does not impede upon such but rather protects it from foreign and native coercion and fraudulence. Free trade is a natural effect of our free will and is the best means of enriching ourselves and our communities.
Thus conservatism was not some radical break from precedent that occurred in the late 17th century, but rather a philosophical tradition already developing in Europe (and arguably had been developing for many centuries). It was finally given its best example in 1787, with the creation of the US constitution, which better exemplified the promise of the Declaration of Independence (classical liberalism). That all men are created equal in the eyes of their creator, and that they have a right to life, liberty, and the pursuit of happiness.