Italy, up to 2 years of Tax Treaty

2 years of teaching/research tax treaty with unlimited exemption

Tax treaty for Professors, Teachers, and Researchers

A professor or teacher who is a resident of Italy immediately before the date of arrival in the United States and whose visit to the United States is expected to last no more than 2 years to teach or conduct research at a university, college, school, or other recognized educational institution, or at a medical facility primarily funded from government sources, is exempt from U.S. income tax for up to 2 years on pay from this teaching or research.

This exemption does not apply to income from research carried on mainly for the private benefit of any person rather than in the public interest.

(Reported from Internal Revenue Service (IRS), US government Publication 901)