In this paper we will discuss some of the issues related to the attempts of Ralph Howard Fowler and Nevil Vincent Sidgwick to create a legitimizing space for quantum and theoretical chemistry in Britain. Although neither Fowler nor Sidgwick made original contributions to quantum chemistry, they followed closely the developments in the discipline, participated in meetings and discussions and delivered lectures, talks and addresses, where methodological topics, ontological questions and implicitly the problem of autonomy of the new discipline vis-à-vis both physics and chemistry were taken to be pressing issues. In particular, they encouraged young people to work within the nascent discipline. Viewing quantum chemistry as a branch of applied mathematics became an emblematic characteristic of the practice of the new discipline in Great Britain.