Detailed Instructions: 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.
Q: One check on a magistrate's power was his collegiality. Each magisterial office would be held concurrently by at least two people. Another such check was provocatio. Provocatio was a primordial form of due process. It was a precursor to habeas corpus. If any magistrate tried to use the powers of the state against a citizen, that citizen could appeal the decision of the magistrate to a tribune. In addition, once a magistrate's one-year term of office expired, he would have to wait ten years before serving in that office again. This created problems for some consuls and praetors, and these magistrates would occasionally have their imperium extended. In effect, they would retain the powers of the office (as a promagistrate), without officially holding that office.
A:
How long concurrently could an elected magistrate serve in office?