What theory did Giordano Bruno defend in his Oxford lectures?

During his time at Oxford in the summer of 1583, Giordano Bruno delivered a series of lectures in which he defended the Copernican theory, specifically maintaining the reality of the movement of Earth.1

While Bruno is widely recognized for his broader, more radical theories regarding an infinite universe and the multiplicity of worlds—which went beyond the traditional heliocentric model—his specific lectures at Oxford focused on the defense of the Copernican system's assertion that the Earth moves. His presentation of these ideas was met with a hostile reception from the scholars at Oxford.21