Bing found the following results
But then Definition & Meaning - Merriam-Webster
How To Use “But Then” In A Sentence: In-Depth Exploration
BUT THEN definition and meaning | Collins English Dictionary
BUT THEN - Find out everything about this English word | Collins
But then - Definition, Meaning & Synonyms | Vocabulary.com
But then - Idioms by The Free Dictionary
BUT THEN (AGAIN) | English meaning - Cambridge Dictionary
but then - Wiktionary, the free dictionary
but then | English examples in context | Ludwig
Usage of "but then" - English Language Learners Stack Exchange