Roman texts on leadership

[GenosseGeneral]

Hi everybody,
somehow I ended up taking a class on leadership this semester and all those 'great' and 'revolutionary' leadership styles and theories they teach us are in my opinion just common sense not as new. To be more precise, I fell like I have read a good share of that stuff , before - in my latin class at school.
After all, I would like to compare 2 millenia old advice on leadership with the eternal wisdom and endless of B. Bass et al. and possibly use the results for a presentation next week.
The only thing is: whereas I am certain that there is extensive writing about leadership from antiquity, I have some trouble remembering the actual sources I read 2-4 years ago.
For instance, I remember that there was some text about Hannibal and how he was a great leader and role model to his soldiers. I think it was by Polybius. Could anyone give me a hint where or how I can find that passage and similar texts?
After all, I would like to point out to my fellow students how 'new' the ideas behind 'transformational leadership' and all that other are.
Thank you in advance,
GG