What's the level of mutual intelligibility/transferrenc between ancient/modern Greek?

[athanaric]

I am not qualified to comment on similarities of ancient and modern Greek, but ancient Greek has many similarities to Latin. [...]

And both have many similarities to Modern, Middle and Ancient Persian. And Sanskrit. That only proves that they are all Indo-European languages though, belonging to different branches. Greek is a branch of its own (together with some other, now extinct, dialects) and not an Italic language.