Final answer:
Percy Bysshe Shelley eloped with Mary Wollstonecraft Goodwin, later known as Mary Shelley, to Italy and kept their marriage a secret due to familial disapproval and Shelley's controversial views and lifestyle.
Step-by-step explanation:
The individual who eloped to Italy and kept his/her marriage secret due to a tyrannical father’s disapproval was Percy Bysshe Shelley. Percy Bysshe Shelley was a radical poet of the Romantic period who faced criticism for his societal views and personal conduct. Shelley met and fell in love with Mary Wollstonecraft Goodwin, known as Mary Shelley, while he was still married to Harriet Westbrook. Their mutual attraction led them to elope, first to Switzerland and then to Italy, where they spent their lives among other English expatriates. During this period, Mary wrote the famous novel Frankenstein. The marriage was kept a secret due to Percy Shelley's estrangement with his family, which resulted from his controversial lifestyle and unorthodox ideas.