Joshua 21:1

‘ Then came near the heads of the fathers of the Levites, to Eleazar the priest, and to Joshua, the son of Nun, and to the heads of the fathers of the tribes of the children of Israel.'

The land having been allocated, and cities of refuge appointed, the Levites now came to remind the leaders, who had accomplished the work, of God's promise to them that cities with lands for their use would be allocated to them throughout Israel. Note the hierarchy, ‘the heads of the fathers'. The princes of the sub-tribes (the thousands?) were over the fathers of the extended families (the hundreds?), who were over the fathers of the closer families (the tens?). These princes then approached the priest of the central sanctuary, and Joshua their great leader, and the princes of the other tribes.