History:

Its more like a personal name ("Ratan") plus a respectful title ("Bhai"). Basically, its history is tied to how names changed in a certain area over time.

Description:

Its more like a nickname – a common name combined with "bhai" (brother). This means its connection to any community depends entirely on the persons family history and where theyre from.

Ratanbhais surname is interesting because its a combination of a first name and a fathers name. "Ratan" is one, just using the first name. "Ratanji" is another, a common way to show fathers name in Gujarati. Theres also a less common possibility, "Ratambhai," depending on how its spelled in different places. These show how this surname has changed over time and in different areas.