Starting with Socrates (469-399 B.C.E.), often referred to as the "first moralist," early Greek morality articulated a system of morality and a code of ethics that maintained the tangible existence of rightness and wrongness in what is best described as a perfect heaven, a realm of existence distinct from our world, but upon which our world relies. Articulated best in Plato's (429-347 B.C.E.) Socratic dialogue "The Republic," early Greeks believed that just as there is a perfect Idea or Form of a chair (of which all other chairs are lesser derivations), so too is there a perfect Idea or Form of rightness and wrongness. Early Greek moralists believed that we access these Forms through philosophical and reflective analysis.
Hellenistic and Roman moralists, most notably Epicureans and Stoics, denied the existence of some ethereal, ineffable ideal heaven in which perfect Forms of objects and concepts exist. Instead, these types of moralists maintained the primacy and importance of morality as it exists within each of us. Both Epicureans and Stoics focused on living a virtuous and peaceful life untroubled by worldly distractions. Both believed humans to be naturally moral beings that are subject to distraction and disruption by worldly pursuits. Accessing one's natural moral virtuousness requires rejection of these pursuits and distractions through meditative and reflective practices.
Moving from an Idealized heaven and an internally existent moral perfection, early Judeo-Christian moralists believed morality to exist in the many interactions within humanity. Distinct, in some ways, from their beliefs pertaining to divinity and faith, the moral system of early Christianity posited that virtue and righteousness does not simply exist; it must be generated. They believed humans accessed or generated this virtue and righteousness through their behavior and attitude toward other humans. This belief is perhaps best encapsulated in the Old and New Testament commandment (known as the Golden Rule): Treat others as you would have them treat you.
Not pertaining to contemporaneity, "modern" moralists are so called as they represent the first cohesive batch of systematic moral thinking following the Dark Ages. Starting with Thomas Hobbes (1588-1679) and extending through to John Stuart Mill (1806-1873), they represented a diverse range of moral systems, most of which are united by their reliance upon a distinct division between the reason and rationality (the mind) and the natural world (the body). Known as Cartesian duality (after Rene Descartes, 1596-1650), the split between reason and nature necessitated the position that any system of morality is fundamentally a rational system, accessed only through logical deduction and argumentation.