In spite of the fact that I'm focusing on Italian, I wanted to take a break for a moment to talk about one of the many things I love about the Russian language. When learning the days of the week, I find it helpful to understand where the names come from. In Russian, this ended up being super-easy!
Monday - Понедельник
The Russian prefix по- indicates something incremental, and a неделя is a "week". So it's easy to recognize that on понедельник we increment the week, ie, start a new one.
Tuesday - Вторник
The word второй means "second", so вторник is the second day of the week!
Wednesday - Среда
The word среда literally means middle, and just as we call Wednesday "hump day", Russians also recognize it as the "middle" of the week.
Thursday - Четверг
The word четвертый means "fourth", so четверг is obviously the fourth day of the week.
Friday - Пятница
And the number five is пять, so пятница is "day number five".
Saturday - Суббота
The name суббота, just like the Italian word sabato, finds its roots all the way back at the Hebrew word shabbat, meaning "sabbath" or "seventh" day.
Sunday - Воскресение
And finally, the prefix вос- indicates motion upwards, and крест is "cross", so you wouldn't be laughed at for thinking воскресать meant "to crucify", but it actually means "to rise from the dead", so воскресение means "the resurrection".