1-The inscription on the seal of the Holy Prophet (PBUH) reads “Muhammad Rasool Allah” which literally means that Muhammad is the Messenger of Allah. This is the inscription which was on the original seal which had been used by the Prophet to sign the letters which he used to send to various rulers of other countries.
2-Anas Ibn Malik stated that the Prophet (PBUH) had a ring which was made up of silver and the inlaid gem was also silver. When the Holy Prophet wanted to write to any of the leaders of foreign states, he ordered a seal ring to be made for the purpose. The Prophet (PBUH) would, therefore, have a ring made, which was so white that its whiteness is still in my eyes. The inscription engraved on the ring of the Holy Prophet (PBUH) had “Muhammad Rasoolullah”. On the first line was “Muhammad”, the second line had “Rasool” and the third line had “Allah” written on it.
3-The Holy Prophet (Peace be upon him) was illiterate, so is common knowledge, hence he had this ring made into his signature seal. And indeed the Holy Prophet (PBUH) had this ring cast in silver, however, He had so much love and respect for the almighty Allah that he did not allow his name to be written above the name of Allah. In contradiction to the regular way of reading which is from top to bottom, the inscription was made a bottom to up.
4-The original ring of the Holy Prophet was lost when it went down the well of Aris during the caliphate of Hazrat Uthman (RA). The seal which is placed in the Topkapi Palace, Istanbul had been made after that, which is not an exact replica of the original ring which had never been recovered from the well.
5-Anas Narrated; When Hazrat Abu Bakr (RA) had become the Caliph; he wrote a letter to him, which had been stamped with the seal of the Holy Prophet. The engraving on the ring was in three lines. Mohammad was on one line, Apostle in the other, and Allah in the third line. Anas added that the ring of the Holy Prophet was in his own hand, after which it was in the hands of Abu Bakr (RA). After that, it went into the hands of Caliph Umar (RA) after which it went to Hazrat Uthman (RA).
6-During his caliphate, Hazrat Uthman (RA) had been sitting at the well of Aris. He had removed the ring and started trifling with it. Suddenly he dropped it into the well. We kept going to the well with Caliph Usman for three days in search of the ring. Finally, the well was also drained, however, the ring could not be found.