premise: From 1016 to 1030 the Normans were pure mercenaries, serving either Byzantines or Lombards, and then Sergius of Naples, by installing their leader Rainulf in the fortress of Aversa in 1030, gave them their first pied-à-terre and they began an organized conquest of the land.
hypothesis: Between 1016 and 1030 was about 14 years.
reason: 1030 - 1016 = 14, therefore the statement "Between 1016 and 1030 was about 14 years." is definitely correct. 