Prophet Muhammad's, sallallaahu alayhi wa sallam, first marriage to Khadeejah, may Allaah be pleased with her, was sponsored by Waraqah Ibn Nawfal, who was a clergyman (priest). Muhammad did not marry any other woman beside Khadeejah for 25 years; meanwhile he got married to more than other 13 women after she passed away. Was their marriage a Catholic one? I am looking for reasonable proofs rather than Qur'anic or Hadeeth quotes.

All perfect praise be to Allaah, The Lord of the Worlds.  I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

The marriage of the Prophet, sallallaahu ‘alayhi wa sallam, to Khadeejah was not a Catholic or Christian one and we have not come across any evidence that Waraqah ibn Nawfal played a role in her marriage. Rather, the books of biography and history state that it was her uncle 'Amr ibn Asad, who gave her the dowry. This type of marriage was well known in the pre-Islamic era as 'Aa'ishah mentioned in a narration reported by Al-Bukhari.

If you are giving evidence that their marriage was a Catholic one because he did not marry any other woman until she died, then this is not a correct deduction. The scholars stated that the reason why he, sallallaahu ‘alayhi wa sallam, did not marry any other woman while he was married to her was because of his fidelity to her in return for the good she provided him, sallallaahu ‘alayhi wa sallam, with. Ibn Hajar said, “The Prophet, sallallaahu ‘alayhi wa sallam, repaid the good that Khadeejah did for him, sallallaahu ‘alayhi wa sallam, in this world, as he, sallallaahu ‘alayhi wa sallam, did not marry another woman [until she died].”

The matter that is inquired about could not be proven except by text, so it cannot be proven without a text from the Quran, the Sunnah (Prophetic tradition), or from the sources of biographies and authentic history.

Allaah Knows best.