Today’s adverb invano should be familiar to everyone as the English equivalent is nearly identical, except that we provide a space between the two terms (in vain).
Ho cercato di convincerli a scappare, ma è stato tutto invano.
I tried to get them to escape, but it was all in vain.
Interestingly, many Italians mistakenly write invano as in vano, and let’s be honest, this orthographic error is more than understandable. Why? Because it derives from the late Latin in vanus, written separately. In fact, the first commandment in the Bible read: Non assumes nomen Domini Dei tui in vanum, which translates as Non nominare il nome di Dio invano (Thou shalt not take the name of the Lord thy God in vain) in Italian.
The truth is that in ancient literary Italian, up until around the thirteenth century, invano was written as two separate words. A quick glance at the writings of Dante Alighieri and Gaspara Stampa is proof of this.