The fort was built after the Great Fire of Shirekeep in 1567 AN during the reign of Kaiser B'Caw I. Revolts against the Babkhans and Anticans during this period, a consequence of perceptions of foreign influence behind the secession of Elwynn from the Imperial Republic, led to violence and riots in the streets.
The disorganised and chronically underfunded city guard was unable, and probably unwilling, to prevent the looting and burning of properties owned by foreigners during this disturbance - indeed they were as likely to be the instigators of the spate of house breaking and arson as any other member of society. Urban planning codes never really gained much in the way of popular acceptance in Shirekeep and as such residential properties in the Foreign Quarter, some of which were more than a century old, were spectacularly unsafe in terms of their sheer combustibility. As such, once fire took a hold in one ransacked property, it was practically impossible to prevent the conflagration from spreading along the entire street.
It ended up in one of the largest fires that Shireroth had seen in 1,400 years: the largest parts of the city south of the Elwynn were destroyed. Kaiser B'Caw I gave the order to build a fortress on the place where no longer where any houses left.
During the era when the renamed Foreign Quarter, Lichkeep as it was now known, languished under the paranoid and obstructive misrule of the corpse creature known as Mira Raynoria, Tempus Keep served as the "Lich-Queen's" seat of government, from whence she could hector and occasionally threaten whichever luckless noble was the temporary occupant of Raynor's Keep across the waters on the far bank of the Red Elwynn.
After the destruction of the MoMA Main Building in a Natopian airstrike during the Year of the Four Kaisers and the subsequent collapse of the state government of Lichbrook in 1649, the Keep was requisitioned by the Ministry of Military Affairs to serve as its new headquarters.
The site of the Keep is presently an island following the flooding and abandonment of much of Lichkeep during the 1650s. Guards have been known to answer queries about how the Ministry came into possession of the property with canister shot fired from one of fourscore sentry guns mounted upon the battlements.