Mahayana explicitly rejects the idea of a Creator, just as Theravada does in the Brahmajala Sutta of the Digha Nikaya (and in at least nine other passages). The Mahayana teachers Asanga (4th century), Dharmakirti (7th century), Chandrakirti (7th century), and Shantideva (8th century) each explicitly refuted theism. Among the Mahayana Sutras the Rice Sapling Sutra in its doctrine of causality is understood by His Holiness the Dalai Lama to imply nontheism (see his remarks in Healing Anger). The idea of a Creator is excluded by several basic Buddhist doctrines, including Not-Self, shunyata, the impermanence of all samskaras, dependent origination, and karma and rebirth.
I am not aware of any "followers of Mahayana" espousing theism prior to the 20th century. The view is heterodox.
namo bhagavate śākyamunaye tathāgatāyārhate samyaksaṁbuddhāya | namaḥ sarvabuddhabodhisattvebhyaḥ ||
"Bodhisattva-mahāsattvas love all beings in the world equally, as if each were their only child..." Buddhāvataṃsakamahāvaipulya Sūtra