Although there is a genealogy indicating Muramune as an adopted child of Norimune, Norikage URAGAMI, or Sukemune, there is no historical materials which support that genealogy.
則宗、浦上則景、祐宗らの養子として系図を繋げる文献もあるが、証拠と裏付けられるだけの史料は無い。