It was created by American programmer Terry A. Davis, who developed it alone over the course of a decade after a series of manic episodes that he later described as a revelation from God.

Programmer Terry A. Davis (1969–2018) began experiencing regular manic episodes in 1996, leading him to numerous stays at mental hospitals.

[1] He suffered from delusions of space aliens and government agents that left him briefly hospitalized for his mental health issues.

[7] TempleOS is a 64-bit, non-preemptive multi-tasking,[8] multi-cored, public domain, open source, ring-0-only, single address space, non-networked, PC operating system for recreational programming.

The stopwatch is meant to act as an oracle that generates pseudo-random text, something Davis likened to a Ouija board and glossolalia.

[5] An example of generated text follows: among consigned penally result perverseness checked stated held sensation reasonings skies adversity Dakota lip Suffer approached enact displacing feast Canst pearl doing alms comprehendeth nought[5]TempleOS was written in a programming language developed by Davis as a middle ground between C and C++, originally called "C+" (C Plus), later renamed to "Holy C", possibly a reference to the Holy See.

Due to TempleOS's niche position, Holy C adoption remains limited outside of that specific operating system.

Online resources exist for those interested in learning more about Holy C, including tutorials and a standalone compiler that facilitates experimentation independent of TempleOS.

Tech journalist David Cassel opined that "programming websites tried to find the necessary patience and understanding to accommodate Davis".

[3] In his review for TechRepublic, James Sanders concluded that "TempleOS is a testament to the dedication and passion of one man displaying his technological prowess.

[7] He added that it "actually boggles my mind that one man wrote all that" and that it was "hard for a layperson to understand what a phenomenal achievement" it is to write an entire operating system alone.