How many time have you heard some one say "Chivalry is dead?" This is a sad commentary on the contemporary gentleman.
Most of us grew up learning that there are a few simple actions that a gentleman must do be chivalrous, including being polite, opening doors, and providing assistance to those who need it. The concept of chivalry started in medieval times as one of the customs of knighthood. The qualities idealized by knighthood, such as bravery, courtesy, honor, and gallantry toward women carried forward into modern times as the best practices of a gentleman.
While the origins of chivalry involve a knight doing anything to honor, serve, and never displease a lady, a true gentleman offers these courtesies to all. Open the door for anyone, not just women. Help all those in need, lot just a pretty lady. If you are attempting to bring out your gentlemanly side in front of a lady (never a bad move), then chivalrous actions are the order of the day.
Here are a few interesting pages on the subject:
Medieval Chivalry
A Lesson in Modern Chivalry and Gentlemen's Etiquette - Daily Nexus
A Code of Chivalry