The phrase "came to be" refers to the beginning or creation of something. However, if you are looking for synonyms to consider using in place of this common phrase, there are plenty of options to choose from. Words like arose, developed, emerged, formed, originated, spawned, and surfaced are all effective replacements that convey a sense of the process that led to the thing's existence. Other potential alternatives include materialized, appeared, debuted, started, launched, established, and took shape. Ultimately, the best synonym will depend on the specific context and tone of your writing, so be sure to choose one that fits the situation appropriately.