 Khitan marriage practices differed from those of the Han Chinese in several ways . Men from the elite classes tended to marry women from the generation their senior . While this did not necessarily mean that there would be a large gap in ages between husband and wife , it was often the case . Among the ruling Yelü clan , the average age that boys married was sixteen , while the average age that girls married was between sixteen and twenty @-@ two . Although rare , ages as young as twelve were recorded , for both boys and girls . A special variety of polygamy known as sororate , in which a man would marry two or more women who were sisters , was practiced among the Liao elite . Polygamy was not restricted only to sororate , with some men having three or more wives , only some of whom were sisters . Sororate continued throughout the length of the Liao dynasty , despite laws banning the practice . Over the course of the dynasty , the Liao elite moved away from polygamy and towards the Han Chinese system of having one wife and one or more concubines . This was done largely to smooth over the process of inheritance . 
