Research into accounting change has examined the evolution of accounting in response to local, time-specific factors. This paper explores this issue in the context of Canadian accounting practice prior to the introduction of the Ontario Companies Act 1907. The major thesis is that accounting thought and practice were generally harmonised, with the 1907 Act tending to lag rather than lead their development. The key link in this harmonisation was the accounting profession, specifically the Institute of Chartered Accountants of Ontario, which developed and publicised accounting thought, designed educational programmes, and influenced the regulatory process. After developing the historical context, a general accounting model is developed in terms of attributes outlined in textbooks published before 1907. This model is compared to the actual records of a sample of firms. Finally, the links between the model, actual practice and the 1907 legislation are explored.