remember the Sabbath episode 4

The 4th commandment, says,"Remember the sabbath day to keep it Holy"
In this series of teachings , we learn about the 7th day sabbath and what importance it holds for Christians. For many Christians, Sunday holds the importance of worshiping on the first day of the week, but how and why was the 7th day sabbath replaced with a first day observance? This series will show you who, why and when the sabbath was changed.