Complex sentence: Of the three Seattle general circulation dailies ("Seattle Post-Intelligencer " and"Seattle Times" being the other two), it was the smallest in circulation, although it had been the largest paper in the city around 1900.
Split into simpler sentences: Of the three Seattle general circulation dailies, ("Seattle Post-Intelligencer " and"Seattle Times" being the other two), it was the smallest in circulation. A significant change from when it was the largest paper in the city around 1900.