These are generally sung at drinking parties and/or during celebrations such as weddings. Kgoshi – a loose collection of kinsmen with related males at its core – was as much a jural unit as a kinship one, since membership was defined by acceptance of the kgoro-head's authority rather than primarily by descent. Royal or chiefly kgoros sometimes underwent rapid subdivision as sons contended for positions of authority. Marriage was patrilocal. Polygamy was practised mostly by people of higher, especially chiefly, status. Marriage was preferred with a close or classificatory cousin, especially a mother's brother's daughter, but this preference was most often realised in the case of ruling or chiefly families. Practised by the ruling dynasty, during its period of dominance, it represented a system of political integration and control recycling of bridewealth (dikgomo di boela shakeng; returning of bride cattle). Cousin marriage meant that the two sets of prospective in-laws were closely connected even before the event of marriage, and went along with an ideology of sibling-linkage, through which the bogadi (bridewealth) procured for a daughter's marriage would in turn be used to get a bride for her brother, and he would repay his sister by offering a daughter to her son in marriage. Cousin marriage is still practised, but less frequently. Polygyny too is now rare, many marriages end in divorce or separation, and a large number of young women remain single and raise their children in small (and often very poor) female-headed households. But new forms of domestic co-operation have come into being, often between brothers and sisters, or matrilineally linked relatives. Previously the oldest son of a household within a polygynous family would inherit the house-property of his mother, including its cattle, and was supposed to act as custodian of these goods for the benefit of the household's other children. With the decline of cattle-keeping and the sharp increase in land-shortage, this has switched to a system of last-born inheritance, primarily of land. The life-cycle for both sexes was differentiated by important rituals. Both girls and boys underwent initiation. Boys (bašemane, later mašoboro) spent their youth looking after cattle at remote outposts, in the company of peers and older youths. Circumcision and initiation at koma (initiation school), held about once every five years, socialised youths into groups of cohorts or regiments (mephato) bearing the leader's name, whose members then maintained lifelong loyalty to each other, and often travelled together to find work on the farms or on the mines.