。
At last dawn broke, and the long night ended.
Literal
Finally night [subject-が] opened [and-て] long night [subject-が] ended.
Poetic/narrative writing. 夜が明ける ('dawn breaks,' literally 'night opens') is a fixed idiom — the same meaning pattern as English 'dawn breaks' but with different metaphorical content. Note that the sentence mentions 'night' twice: 夜 as subject of 明ける and 長い夜 as subject of 終わる — the parallelism creates a sense of closure. ようやく ('at last') conveys long-awaited arrival.