Mr. Denis Lennon and Mary Mullin were actually eloping to the United States together, hence the shroud of secrecy and the reason why the two are listed as brother and sister. The truth is Denis found a job as barman in the Mullin family's general store/pub in Clarinbridge, Co. Galway. He fell in love with Mary, however the upwardly mobile Mullin family forbade such a romance between a humble barman and their daughter. The young couple, desperate and in love decided to elope to the States. Originally booked on the "Celtic" they were transferred to the "Titanic." They had been pursued to Queenstown by Mary's older brother who was supposedly armed with a gun (he had been tasked with retrieving their tear away daughter). Nonetheless, the brother arrived by train too late and just missed the "Titanic's" tender. Hence the couple sailed off into destiny and disaster unhindered in their flight. Sadly the two were lost, but the story truly echoes the fictional romance of Jack and Rose in the film "Titanic" - love across the class divide, perusal by a gun-welding relative, eternal unity through death.....The only thing is - this really happened!

(Note: I Edited the spelling)

Originally posted on: http://www.encyclopedia-titanica.org/biography.php/lennon_denis_973.html

Well if this did really happen it makes you wonder if that wasnt at least somewhat, what the characters of Jack and Rose were based on.