This is a bit of a strange one, but I'll put it out there just in case.
My g-g-grandfather John Timbrell Milward Pierce (aka John Pierce-Hope), born in England in 1862, ended up for various complicated reasons living in Bolivia, and at some point between about 1895 and 1910 served as Minister for Public Works in the Bolivian government. His service ended, according to a family reminiscence, because Bolivian law was changed so that only citizens of the country could occupy government office.
If anybody had any ideas as to how I can pin down the dates and details of his government appointment I'd be most grateful.