Task: Question Generation
Input (English): In June 2005, presidential elections were held for the first time since the coup that deposed Ialá. Ialá returned as the candidate for the PRS, claiming to be the legitimate president of the country, but the election was won by former president João Bernardo Vieira, deposed in the 1999 coup. Vieira beat Malam Bacai Sanhá in a runoff election. Sanhá initially refused to concede, claiming that tampering and electoral fraud occurred in two constituencies including the capital, Bissau.
Output (English): When was Vieira, a former president, deposed?