Complex sentence: Between 1970 and 1984 in Portugal, "Dona Branca" maintained a Ponzi scheme that paid a ten percent monthly interest, for that she became known as "The people's banker".
Split into simpler sentences: Between 1970 and 1984 in Portugal, "Dona Branca" maintained a Ponzi scheme that paid a ten percent monthly interest. She became known as "The people's banker".