Complex sentence: The Louisiana Purchase Sesquicentennial half dollar was a proposed commemorative coin in 1952, presented by both the Missouri Historical Society (MHS) and the Louisiana Purchase 150th Anniversary Association, to celebrate the 150th year anniversary of the Louisiana Purchase.
Split into simpler sentences: The Louisiana Purchase Sesquicentennial half dollar was a proposed commemorative coin in 1952. Proposed by both the Missouri Historical Society (MHS) and the Louisiana Purchase 150th Anniversary Association, the coin was intended to celebrate the 150th year anniversary of the Louisiana Purchase.