Italian hymn (?) sampled in Mark 'Oh - Tears Don't Lie

I've wondered about this for a long time, but after something I experienced today, I finally had to ask you guys about it.

Today, I walked past this Peruvian street musician playing his pan flute and guitar, and he played a song extremely similar to "Tears Don't Lie" by Mark 'Oh. Only slightly melodic and harmonic differences. I couldn't get anything out of him other than smiles and nods, so it was no use asking him. According to danceartistinfo.com, it's an Italian hymn, but the question is: What's it called?

"Soleado" covered many times...maybe the original is Antonio Zacara da Teramo.
in the 70s Michael Holm had a big success with this theme (Tränen Lügen Nicht), it was the inspiration for the Mark Oh project.

Thanks matteo! :)