Romana was a Time Lady from Gallifrey. The White Guardian assigns Romana to assist the Fourth Doctor during the quest for The Key to Time-Wasting. She then continues to travel with him for a season of The Fourth Doctor Adventures to help the Laan return to THE SANDS OF LIFE.
Romana is the classiest Dame around. Managed to not be overpowered by the performance of Tom's scarf.
Mary Tamm died in 2012 and is probably now partying it up with Jon "YOU BETTA SPLINK" Pertwee. She was friends with K9 and helped the Fourth Doctor hunt down the Key to Time which was supposed to open the chest to the Missing episodes. The ending was anti-climactic as heck though. Either way, Romana was worthy. You were the noblest of them all, Mary Tamm.