Warden of Time. The After Cilmeri Series, #8

Warden of Time continues the story of time travel, romance, and adventure that began with Daughter of Time . As both modern man and medieval king, David is committed to transforming medieval England into his own version of Avalon. But not everyone supports his ideals, and having offended the pope by welcoming Jews and heretics into England, David is summoned to Canterbury to explain himself. When information comes to light that reveals the accusations against him have less to do with religion than with power and wealth, David finds himself on familiar ground-and at the center of a conspiracy that stretches from Ireland to Italy.
Facing excommunication, a fickle populace, and rebellion even by his fellow time travelers, he must decide what his throne is worth, and what he's willing to sacrifice to keep it. Complete Series reading order: Daughter of Time, Footsteps in Time, Winds of Time, Prince of Time, Crossroads in Time, Children of Time, Exiles in Time, Castaways in Time, Ashes of Time, Warden of Time, Guardians of Time.
Masters of Time, Outpost in Time, Shades of Time, Champions of Time, Refuge in Time, Unbroken in Time, Outcasts in Time, Hidden in Time, Legacy of Time, Renegades in Time. Also, This Small Corner of Time: The After Cilmeri Series Companion.