Linked from
The 10 pages that link to Lothair I, each with the reason it gives.
Treaty of VerdunRelated: He received the imperial title and the central kingdom in the settlement.
Louis the PiousRelated: Louis’s plans gave Lothair senior status, but not uncontested control.
Middle FranciaRelated: He received Middle Francia and its imperial title in the partition.
Louis II of ItalyRelated: Louis inherited Italy from his father, Lothair I.