Convert from tonelada [Portugal] to libra [ancient Rome]

Unit Definition (tonelada [Portugal])
The tonelada [Portugal] is a traditional weight unit of Portugal corresponding to the English and metric ton. The Portuguese tonelada, however, equals 1728 Portuguese libras or arratels; this is about 1748.6 pounds or 793.15 kilograms.

Unit Definition (libra [ancient Rome])
The libra [ancient Rome] is a traditional unit of weight. The libra was the Roman unit from which the English pound is descended; the symbol "lb" for the pound comes from this unit. The Roman libra contained only 12 unciae (ounces) and was about 0.722 English pound. The word "libra" is sometimes used now for the kilogram, a much larger unit.