Who developed dbms?

What were the largest cities in Europe in 1600's? How long were the crusades? The Crusades revived European business and trade? Why was it necessary to have three Punic wars? The end of the Roman Republic and the beginning of the Roman Empire occurred in about 31 BCE. This occurrence was influenced by the death of which of these rulers? How did the fashion change since the 1950's until now? What are the 3 major characteristics of the holy roman empire? What jobs did medieval villagers do? When was dating invented? Who were to leaders who fought in the crusades? What is another word for the west with the word dent in it? How did the Romans finally change their government after 200 years of harsh monarchic rule? What is greater 1 millennium or 10 centuries? What was the first armor of a roman soldier like? Technological advances in mining and in agriculture that promoted the development of the western economy in the late 1800's? How can you download horrible histories songs? What do you think is a more reliable source of wealth from conquered kingdoms? When did the fifth crusade take place? How did Plebeians gain power in Rome? Did the ancient Roman legal system stress the rights of the individual over the authority of the government?