The monster figures out the history of the family, the De Laceys. Safie's father was a wealthy "Turk" living in Paris, who was wrongly accused of a crime. Felix offered to help the Turk escape from prison, and meanwhile fell in love with Safie. The Turk offered Felix his daughter's hand in marriage in exchange for helping the two escape. Felix, Safie, and her father escaped and made it to Italy, but then Felix's role in the conspiracy was discovered, and as a result the De Laceys lost their wealth and were exiled by the government. Felix returned to help his family, assuming that the Turk would uphold his end of the bargain, but the "treacherous Turk" decided he didn't want his daughter to marry a Christian. Safie's "Christian Arab" mother had taught her to be independent and intellectually curious, however—traits not encouraged among women in her father's Islamic society—so when Safie's father tried to force her to return to Turkey with him, she escaped and came to find Felix.
All kinds of human fallibilities are at work here: Safie's father is a falsely condemned criminal and promise-breaker, Felix is a conspirator, and marriage, a supposedly pure union of souls, needs to be brokered like an illicit business deal. It should also be noted that Shelley draws a clear divide between Christianity as "enlightened" and Islam as "childish"—a biased, Eurocentric vision of the world typical for her time and place.