What did nelson mandela learn from prison?

There were many changes that Mandela fought for and won during his time at Robben Island. Some of them are:

1) Letting blacks have long trousers

2) Giving the blacks bread

3) establishing a tennis court in the courtyard.

4)Giving prisoners desks and chairs to study.

5) Letting political prisoners buy newspapers

AND MOST IMPORTANTLY

6) Ending manual labour.