Lemaitre is rightly credited with the proposal of what became the Big Bang theory, and the Hubble constant should probably be called the Lemaitre-Hubble constant, but let's give credit where credit is due. Robert Grosseteste was 700 years ahead of his fellow cleric.

It seems that Robert Grosseteste was a man ahead of his time. He was a theologian and philosopher who, in a recently translated Latin text, written in 1225, proposed that the Universe started with a flash of light. In those days Aristotle’s idea that the Universe was composed of a number of concentric, Earth centred, crystal spheres was gaining popularity; and this is how Grosseteste saw things. However, when modern mathematics and physics were applied to his original text, it appeared that he had foreshadowed not only the Big Bang, but also multiple universes.

There never was nothing.