Check the Historical Map Themes for Marble from 1744 and 1786

edu.kde.org/marble/maps-4.5.php

Compare them with the legends inside the Historical Moon maps.

Research background information about the maps from 1744 and 1786 like the author, picture of the author, interesting aspects of the map. The information added should have the same amount as for the Historical Moon maps. It should also be presented the same way. 

The 1786 map's legend should especially mention the fact that the map contains the tracks of James Cook and do a few explanations there.

Also add "Recommended Links" if applicable and the License the same way as for the Historic Moon maps.

For all this you need to adjust the legend.html file and possibly the dgml file. To learn more about the dgml file check out http://techbase.kde.org/Projects/Marble/CustomMaps