When was the Quran revealed to the first heaven and subsequently to the Prophet?

Primary text

Gabriel brought the Quran down from the House of Might (Bayt al-'Izza) to the lowest heaven on Laylat al-Qadr. It was then revealed piecemeal to the Prophet, peace be upon him, over twenty-three years. Laylat al-Qadr remains established and was not removed, as affirmed by the Prophet, peace be upon him, in response to Abu Dharr's query, stating it remains until the Day of Resurrection and occurs in Ramadan, specifically in the last ten nights.