  We investigate how the solution to the strong CP problem and the explanation
for the observed fermion mass hierarchies can be intrinsically related.
Specifically, we explore the Nelson-Barr mechanism and identify its "seesaw
limit", where light quark masses are suppressed by large CP-violating terms.
Upon adding three (two) vector-like quarks that mix with the down-type
(up-type) quark sector of the Standard Model, we demonstrate how the lack of CP
violation in the strong sector and the observed quark mass hierarchy can be
simultaneously achieved.
