Yume no Shizuku, Ougon no Torikago

Beginning of 16th century, Alexandra was captured by slave traders from Ukraine during one of their many raids. When the traders arrived in Greece to sell the female slaves, a young handsome man named Mateus bought her and promised to give her true freedom. He hired countless teachers, scholars, and palace ladies to train her into the most perfect woman of her time. Mateus's kindness has caused Alexandra to deeply fall in love with him, and she secretly wishes to be his concubine. But cruel fate! Mateus has already promised her to his best friend?