The "integral" tendency began with Hegel

The Integral movement in social and historical context
Integral Esotericism - Part Two Alan Kazlev 2-vi. The Integral movement

It might be said that the integralising and integrating tendency has arisen many times as the counter-reaction to, but also the natural result of, the tendency towards specialisation and fragmentation of knowledge that characterises the modern secular Western worldview. Thus the term "integral movement" need not refer only to recent attempts at unification such as in Wilberian and post-Wilberian thought, but can be used to designate previous thinkers and teachers who had this aim or offered this, even if they didn't call themselves "integral"(as the word itself in this context was only first coined by Sri Aurobindo, and later, independently[7], by Jean Gebser).

As far as secular modernity goes, the "integral" tendency began with Hegel, and has been a continuing trend in western philosophical and scientific thought ever since. Wilber's AQAL (all quadrants all levels) Integral theory constitutes simply one possible version of this. Integral philosophy thus pertains to the unification and integration of all scientific-empirical, socio-cultural, and psychological-religious-consciousness-spiritual knowledge. However, for a truly integral and all-inclusive understanding one should also include esotericism here (including esoteric integralism as presented by Theon, Blavatsky, Steiner, Hermeticism, etc), and in fact any philosophy that explains the various elements and aspects of reality; it doesn't have to be a secular-based philosophy or science.