Complex sentence: Some journalists wrote for more than one newspaper and several papers had more than one journalist in Spain at the same time or at different times, and in some cases, they were already seasoned war correspondents when they went to Spain.
Split into simpler sentences: Some journalists wrote for more than one newspaper and several papers had more than one journalist in Spain at the same time or at different times. In some cases, they were already seasoned war correspondents when they went to Spain.