 Complete the following phrase:  While commemoratives had honored Civil War figures and events in such stamp issues as the Army Navy 1937 series and the Centennial celebration of 19611965, comprehensive coverage of the conflict did not appear until 1995, when U.S. Postal Service issued its most ambitious commemorative of the Civil War to date in photogravure sheets of 120 in six panes of 20. The four events pictured were 