Note 91 — Chapter VI · CAROLINGIAN AND ITALIAN EMPERORS.
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The accession of Boso took place in A.D. 877, eleven years before Charles the Fat's death. But the new kingdom could not be considered legally settled until the latter date, and its establishment is at any rate a part of that general break-up of the great Carolingian empire whereof A.D. 888 marks the crisis. See Appendix A at the end.
It is a curious mark of the reverence paid to the Carolingian blood, that Boso, a powerful and ambitious prince, seems to have chiefly rested his claims on the fact that he was husband of Irmingard, daughter of the Emperor Lewis II. Baron de Gingins la Sarraz quotes a charter of his (drawn up when he seems to have doubted whether to call himself king) which begins, 'Ego Boso Dei gratia id quod sum, et coniux mea Irmingardis proles imperialis.'