Complex sentence: Although other New England tribes produced "wampompeag", the Indians of Long Island were reputed to have made the best, making them subject to raids by the Pequot and other New England tribes to control this valuable trade commodity.
Split into simpler sentences: Although other New England tribes produced "wampompeag", the Indians of Long Island were reputed to have made the best. They were subject to raids by the Pequot and other New England tribes to control this valuable trade commodity.