On the 6th of Ramaḍān 201 AH, Imam Alī ibn Mūsā ar-Riḍā (عليه السلام) was appointed as the crown prince. Sayyid Ibn Tawus has mentioned that it is recommended to offer a thanksgiving two-unit prayer in which one should recite Surah al-Fātiḥah once and repeat Surah al-Tawḥīd twenty-five times.
The Sixth Night Prayer: 4 rakat with Surah al-Fātiḥah and Surah al-Mulk (No. 67).
The Sixth Day Supplication