This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

After the death of the replacement bishop Gregory in 345, Constans used his influence to allow Athanasius to return to Alexandria in October 345, amidst the enthusiastic demonstrations of the populace. This began a "golden decade" of peace and prosperity, during which time Athanasius assembled several documents relating to his exiles and returns from exile in the Apology Against the Arians. However, upon Constans's death in 350, another civil war broke out, which left pro-Arian Constantius as sole emperor. An Alexandria local council in 350 replaced (or reaffirmed) Athanasius in his see.
Who did he have to thank for his ability to come back to Alexandria in 345?