Interregnum 1383-1385
House of Aviz[?] 1385-1580
Habsburg
House of Braganza[?] 1640-1807
House of Braganza, Restored 1814-1910
The chronology continues on Presidents of Portugal
See also: History of Portugal -- Lists of incumbents
... to both sides, getting <math>x^2+\frac{b}{a}x+\frac{b^2}{4a^2}=-\frac{c}{a}+\frac{b^2}{4a^2}.</math> The left side is now a perfect square; it is the ...