Complex sentence: New Sweden was first settled in 1637 on territory claimed by Dutch Republic, which was unable to prevent it and did not officially recognize it, and was brought under Dutch control in a military expedition led by Director-General of New Netherland Petrus Stuyvesant in 1655.
Split into simpler sentences: New Sweden was first settled in 1637 on territory claimed by Dutch Republic, which was unable to prevent it and did not officially recognize it. It was again brought under Dutch control in a military expedition led by Director-General of New Netherland Petrus Stuyvesant in 1655.