According to legend, the city of Venice was founded in 421 and there is an oblique reference to that year at the Porta di Terra, the land entrance to the Arsenale.
The entrance is framed by two pairs of marble columns and Inscribed into the bases of the columns are two sets of Roman numerals: MXXXVIIII and MCCCCLX. The latter refers to the year (1460) the Porta di Terra was built, while the former refers to the number of years that had passed since the city was founded, namely 1039.
The numerals are preceded by a Latin phrase: AB URBE CONDITA (from the founding of the city). A simple calculation reveals that 1460 minus 1039 equals 421.
AB URBE CONDITA, often abbreviated to AUC, was most famously used by the ancient Romans, who traced the origin of their city back to the year 753 BCE.