Did the Messenger of Allah, may Allah bless him and grant him peace, supplicate before the prayer or when rising for it?

The opening supplication (Du'a al-Istiftah) is recited after the Takbir (pronouncement of "Allahu Akbar") and before the recitation of Al-Fatiha, according to the majority of scholars. This is because it was not reported that the Prophet (peace be upon him) or his companions recited it before the Takbir. Also, supplication typically comes after the act of worship, as indicated by the verse: ﴿So when you have finished [your duties], then stand up [for worship].﴾