Trajan was a Roman Emperor who ruled from 98 to 117 AD and is best known for leading the empire to its maximum territorial extent through military conquests, particularly in Dacia (modern-day Romania). He is also recognized for his extensive public building programs, including the famous Trajan's Market and Trajan's Column in Rome, which commemorated his victories. Trajan is often regarded as one of the most respected and effective Roman emperors.