The past tense of “being” is “was” or “were,” depending on the subject.
To explain this further, the word “being” is the present participle of the verb “to be.” In English, the verb “to be” has different forms based on the tense and the subject. For singular subjects like “I” or “he/she/it,” we use “was.” For plural subjects such as “we” or “they,” we use “were.” Therefore, when we talk about a state of existence in the past, we choose the appropriate form of ‘to be’ according to the subject we’re discussing.