Willem Kieft was Director of New Netherland from 1638 until 1647. The colony had grown somewhat before his arrival, reaching 8,000 population in 1635. Yet it did not flourish, and Kieft was under pressure to cut costs. At this time, Indian tribes which had signed mutual defense treaties with the Dutch were gathering near the colony due to widespread warfare and dislocation among the tribes to the north. At first, he suggested collecting tribute from the Indians, as was common among the various dominant tribes, but his demands were simply ignored by the Tappan and Wecquaesgeek. Subsequently, a colonist was murdered in an act of revenge for some killings that had taken place years earlier and the Indians refused to turn over the perpetrator. Kieft suggested that they be taught a lesson by ransacking their villages. In an attempt to gain public support, he created the citizens commission the Council of Twelve Men.