What did Muslims recite in prayer instead of Surat Al-Fatiha before its revelation?

Scholars differ on whether Al-Fatihah is Makki or Madani. The preponderant opinion is that it is Makki, based on the Almighty's saying: "And We have certainly given you seven of the often-repeated [verses] and the great Qur'an." [15:87], and Surah Al-Hijr is unanimously Makki. What further supports it being Makki is that the obligation of prayer was established in Mecca, and it is not preserved that it was ever without Al-Fatihah. The Prophet's (PBUH) saying: "There is no prayer without the Opening of the Book," indicates that prayer was not enjoined until after the revelation of Al-Fatihah.