Father Pecerillo, a famous Franciscan Archeologist, found from the Forth Century (200 years before Islam) houses in Syria, Lebanon, Iraq and Palestine with this inscription in Arabic :"Bismi Allah al-Rahman al-Raheem" which means in Arabic "In the name of ALLAH, the Most Merciful and the Most Gracious", which again proves that His Holy name existed before Islam and it also proves the True Oneness of Allah Almighty and refutes Trinity.  Here is an analysis to the Arabic words above:

Bismi - Ism = name. Bism = In name, because "Bi" = in.  Bismi = In the name of, because the "i" at the end of the word must be added because of the "Bi" addition.  When we added "Bi" to the word "Ism", then the "i" must also be added to the end of "Bism" if and only if the word "Bism" is followed by another word, which makes it become all one word "Bismi" which means "In the name of".

Allah - Allah is the name of Allah Almighty.  Bismi Allah sounds as "bismillah", but two seperate words.  "Bismi" is one seperate word and "Allah" is another seperate word.

Al-Rahman - Al = the.  Rahman = merciful.   Rahman is derived from Rahmah, which means mercy.  Al-Rahman is one word.   It is not like English two words "the merciful".  No, in Arabic, "the" is combined with the word both are written as one word; "Al-Rahman".

Al-Raheem - Al = the. Raheem = gracious.  Al-Raheem = the gracious.  Again, Al-Raheem is written as one Arabic word, and not two.