The University of Oxford did not offer a calculus course until the late 1600s
Despite some colleges being over 1,000 years old, the subjects they offered to study were not always the same. The University of Oxford, for example, did not originally include calculus in its courses. This is not because the subject of math was not considered necessary, though.
The truth is that the theory of complex calculus had not been developed yet. Newton and Leibniz, the fathers of complex math, both came up with their ideas in the 1660s and 1670s but did not publish them until the 1680s.