The erection of Roland statues in the 14th an 15th century should be seen against the background of Charlemagne's legend and the adoration of Charlemagne more wide-spread under Emperor Charles IV. An important figure of the Charlemagne legend cycle is Charles' paladin Roland, who has also been worshipped as a saint because he died a martyr's death in the battle against the heathen at Roncesvalles. It is from the 12th century onwards that you find his image on the outside of churches.
It is about the middle of the 13th century that Saxon law and, in particular, the "Sachsenspiegel" came to be considered as imperial law ("Kaiserrecht") set by the Christian rulers Constatine and Charlemagne. As Charles IV. placed himself consciously in the traditional line of succession of Charlemagne, there might be a correlation between his power policy and the erection of Roland statues, especially in Northern Germany and Brandenburg, to symbolize imperial law. The God-given sword "Durendart" carried by Roland symbolizes the divine origin of imperial law. As a general rule, Roland effigies are not placed next to those of Charlemagne (and vice versa) or, otherwise, pre-existing ones are renamed.
The general understanding of symbolism dwindles at the same time as the effigies undergo eventual changes of significance so that each individual Roland has to be interpreted against the background of the time of its erection, the history of the respective town, and other data that might be known.