Complex sentence: Previously a Byzantine palace, known as the "House with the two Towers", stood on the site; this was bought by the Republic of Venice in 1429 from Bernardo Giustinian, to be the residence of the vice-captain of the Republic, Gianfrancesco Gonzaga.
Split into simpler sentences: Previously a Byzantine palace, known as the "House with the two Towers", stood on the site. This was bought by the Republic of Venice in 1429 from Bernardo Giustinian, to be the residence of the vice-captain of the Republic, Gianfrancesco Gonzaga.