Original sentence: A campaign was launched soon after the loss, with the help of the British Museum, to catalog and eventually recover looted works.Appeals by the museum resulted in some items being returned.Many treasures of Mesopotamian archaeology were housed in the Baghdad Museum until 2003, when they were lost to looting and vandalism during the chaos that accompanied the 2003 invasion of Iraq by the United States and allies.Others clearly were stolen by criminal gangs with the intent of sale abroad.The number and value of stolen items are disputed
Edited sentence: A campaign was launched soon after the loss, with the help of the British Museum, to recover as much of the looted works as possible, though it may take decades or even centuries before the collection is back to the level it previously held.Many of the great treasures of Mesopotamian archaeology were housed in the Baghdad Museum, until 2003, when much was lost due to the looting and vandalism that occurred as a consequence of the American military having invaded and taken over Baghdad