I had spotted the discussion but hadn't had the time to respond...
A PhD (Doctorate of Research) is the highest level of study offered by MIUR in Italy. It consists of a research path of at least 3 years to be carried out in accredited institutions (universities, graduate schools, research centers, etc.), at the end of which a doctoral thesis is defended. Despite there being a sort of project whispered about on the web, so far no Italian conservatory has ever launched doctoral courses.
More or less every year, universities hold competitions for PhD positions. The competition is public and has specific terms of access and evaluation. Generally, access is limited to certain academic qualifications (if you have a degree in literature, it is VERY difficult that you can even gain access to a musicology PhD competition), but this already constitutes the first part of the evaluation, the so-called evaluation of qualifications, in which, precisely, the candidate's academic career is assessed (titles, grades, exams taken...). Generally, there are 3 or 4 other steps in the PhD competition: the evaluation of publications (books, articles, and the degree theses themselves presented as evaluable by the commission), the written exam (generally an essay on a topic related to the research), the oral exam (often a discussion of the topic but it can be a general exam on the subject of research), and the evaluation of the research project (sometimes merged with the oral exam). This last one is the most important, because a PhD is not a course of study; it is a research project. You decide to study all the marches for band written by Mozart, so you build a research project and present it to the doctoral commission of a certain musicological faculty. They evaluate you also and above all in light of that project. Then, in theory, they ensure that during the three years you not only carry out the project but also participate in training activities related to the project (for example, I don't know, inviting a great Mozart expert to give a lecture).
There are PhD scholarships which, according to past law, covered at least half of the advertised PhD positions (for example, 4 PhD positions, 2 with scholarships). That law no longer exists and we will see what happens...
A PhD in musicology exists in a few Italian faculties, let's say Cremona, Bologna, Venice, Florence, and Rome (with consortium sites in Naples and Palermo, if I'm not mistaken). In reality, musicological projects are also accepted in other faculties, such as Milan and Turin, but within paths that should be more multidisciplinary (that is, if you want to do research on the librettos of Arrigo Boito, you can also do it in a faculty that does not have musicological experts but has experts in theater history...).
If you want to do a PhD in musicology in Cremona, Bologna, Venice, Florence, and Rome and you don't have a degree in musicology, well, pray to various saints, because there will be quite a few people who do have that degree and who will try to trip you up.
