Two Moon Princess Series by Carmen Ferreiro-Esteban

A Spanish PrincessAn American BoyA King set on revengeAn unrequited loveand a disturbing family secretbring a World to the brink of WarTwo Moon Princess is a coming of age story with a touch of romance that takes place in a mythical world in which the medieval kingdoms of Spain are still fighting each other, a world of warrior kings in which girls are not supposed to speak their minds.

A full moon, A silver key, And the unbending passion of two young lovers will bring hope to a defeated kingdom and, through their sorrow, deliver a king who will change its fate. Sent back in time through a portal the full moon opens, Julian and Andrea, two lovers from a parallel universe, are caught in opposite sides of the battle between the last Spanish stronghold and the Arabian invaders... moreA full moon, A silver key, And the unbending passion of two young lovers will bring hope to a defeated kingdom and, through their sorrow, deliver a king who will change its fate. Sent back in time through a portal the full moon opens, Julian and Andrea, two lovers from a parallel universe, are caught in opposite sides of the battle between the last Spanish stronghold and the Arabian invaders. A battle for survival that will determine the fate of a kingdom and demand of them the ultimate sacrifice: As the Arabs close on the mountains, Julian makes a decision that will break Andrea's heart and change them forever. less