I had the greatest of teachers. I went to a parochial grade school, Holy Trinity Catholic School in Dayton, Ohio, and the nuns - the Sisters of Notre Dame - were my teachers.
These women were all from the same neighbourhoods and the same backgrounds as we were. Their fathers were plumbers, plasterers, electricians, carpenters and factory workers. So they had a very clear understanding of who we were. They were nourishing and inspiring and very compassionate, with a great sense of humour. They provided the foundation that helped me to build my own life.
Teachers are my heroes. I had these extraordinary women who nurtured me when I was a boy; they made all the difference. You don't always realise how dedicated your teachers were until you get older. They provided all the things that we needed from our parents when our parents weren't there. I'm indebted to them.
One is still living - she's 94 and lives in Cincinnati. Her name is Sister Anna Charles and we still correspond. She knew my family, all nine of my siblings, and she always asks about my sister Carmen, who lives in Madrid, and my eight brothers. And she lets me know what's going on.
Your early life - that's the foundation. You start out with a new pair of shoes; by the time you've walked for a while they are not new any more but they are yours. Things change along your journey, everything changes. But you're still supported by the foundation that was built for you. You take those things with you for good and ill, those things that as a child nurtured you and inspired you and made you want to become who you are.
Some children are damaged in childhood; some are abused, neglected and unloved. Their lives are dormant until someone comes along - and very often it's a teacher. Someone who has an independent role, who can start afresh with a child and give them a new view, because they understand their background and their problems. They can give children a new start. That's why teachers are so very important.
In my school, those wonderful nuns could see very clearly what we were bringing. They didn't punish, they didn't scold, they didn't judge - they nourished. They didn't always realise how important they were in our lives, but they gave us another view of adults.
My mother died when I was very young, so my dad worked a lot and he wasn't always able to be present for us. There were so many of us and time was short for him; there was so much work to be done and he was unable to focus on all the day-to-day problems. So we got more nourishment in school and he counted on that - most parents did. They trusted the teachers. There was such gratitude for those teachers when I was a kid, and there was such confidence that they were there for us.
Martin Sheen was talking to Helen Ward
Hello, Mr President
Born 3 August 1940
Education Holy Trinity Catholic School and Chaminade High School, Dayton, Ohio
Career Film and television actor who played fictional US president Josiah Bartlet on TV show The West Wing from 1999 to 2006