For many centuries, in Christian lands (Italy in particular), divorce was outlawed. But Judaism allows divorce. Does anyone know what the Jews did in these countries, if they wanted to divorce? If you got only a religious divorce and married again, you could be accused of bigamy. I searched for the historical record, but could not find it.
You will find the historical information you seek at this link: Italy, Early Modern - Jewish Women's Archives: https://jwa.org/encyclopedia/article/italy-early-modern. It is an encyclopedia article by Howard Tzvi Adelman. Simply put, Jews could indeed divorce in Catholic-dominated Italy, and Adelman discusses the conditions established by the autonomous rabbis.
In other Christian lands the situation was similar. For that information, consult in the same source 'Halachic Decisions on Family Matters in Medieval Jewish Society' by Avraham Grossman:https://jwa.org/.../halakhic-decisions-on-family-matters-in-m... He gives ten of the most important takkanot on family matters. Two are from Babylon from the period of the Geonim, four are from Germany, two from France and two from Spain.