Since the sixth century BCE, Zoroastrians have believed in the supremacy of one God above all: Ahura Mazda as the “Maker of All” and the first being before all others. Nonetheless, Zoroastrianism was not strictly monotheistic because it venerated other yazatas alongside Ahura Mazda. Ancient Hindu theology, meanwhile, was monist, but was not strictly monotheistic in worship because it still maintained the existence of many gods, who were envisioned as aspects of one supreme God, Brahman. Numerous ancient Greek philosophers, including Xenophanes of Colophon and Antisthenes believed in a similar polytheistic monism that came close to monotheism, but fell short. Judaism was the first religion to conceive the notion of a personal monotheistic God within a monist context. The concept of ethical monotheism, which holds that morality stems from God alone and that its laws are unchanging, first occurred in Judaism, but is now a core tenet of most modern monotheistic religions, including Zoroastrianism, Christianity, Islam, Sikhism, and Bahá’í Faith.