Plans advanced in certain days in Rome (5)
I believe the answer is:
ideas
'plans' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for ideas that I've seen before include "Thoughts, personal views" , "thinking" , "Brainwaves" , "Brain waves" , "Thoughts from Sadie" .)