Images of Liberty would remain a standard part of US coinage through the 19th century and into the early 20th. While European coins typically included a portrait of the reigning monarch, the idea of depicting a real, as opposed to an allegorical, figure was considered unacceptable in the republican United States. The image of Liberty used on US coins generally reflected contemporary standards of female beauty, and was redesigned every few decades to reflect the changing times, although the Seated Liberty image which graced coins starting in 1837 would end up being used for over half a century. Not until the Lincoln cent, issued in 1909 to commemorate the centenary of President Lincoln's birth, would a real person be depicted on a US coin.