England and Wales have a sizeable fee-paying private school sector including well-resourced elite schools conferring considerable advantage on their students. The majority have charitable status, yielding substantial tax breaks. This significant source of funding for the sector has attracted comparatively little attention from educational researchers. This paper offers a critical socio-legal historical analysis of the tax treatment of these schools. It demonstrates that they emerged through the complex intersection of tax and charity law over some 400 years. It also shows that, since the 19th century particularly, this involved the purposive intervention of ruling elites in defence of class privilege. Our close analysis of the power relationships involved helps explain why these taxation arrangements have endured over time and have proven so intractable, and offers understandings that might prove valuable in effecting more considered funding strategies for schools.