Yes, captiolium, from the name of one of Rome's seven hills, and home to the temple of Jupitor, is the root to capitol, as in "our nations Capitol"-- and the legislative body there--"Capitol Hill".

a related root word capo– meaning head is at the head of many other words

kaput, capitate, (and decapite) capo, captain, caprice, cape, cap– some have come in through a backdoor– kaput comes in from the german– (headless) or dead. "capitate" to head something-- lead to capital as an Upper case letter, and to money-- as capitol.. I can't remember all the other words where the head is hiding -- but i am sure the list will grow.