Brelian year

The Brelian year was a unit of time used by the Kryptolians, who promised to awaken their Sto-cats and begin their conquest of the universe after "one million Brellian years". As the Fourth Doctor told Sarah Jane Smith, no one actually knew how long a Brelian year was, meaning it was unknown how long Earth had to prepare for the awakening of its own bespoke Sto-cat, the Great Sphinx of Giza. (PROSE: The Sleeping Beast)