The Lent, time of preparation for Easter, appeared in Roman liturgy on the 4th century. It used to start on the first Lent Sunday. In the 6th century its start was put off from that day to Wednesday prior tο the Sunday in question. On that day people doing penance, shortly afterwards followed by other believers, would receive ashes as a sign of entry into the Lenten preparation for Easter. For that reason that Wednesday was named Ash Wednesday. The article analyzes the historical development of the Lent, Ash Wednesday and the basic contents: charity, prayer fasting are contemplated in the context of biblical tradition of the first Church - in order to make a better insight in the internal contents of the today's liturgy of the Ash Wednesday. If during centuries too much emphasis was put on fasting and penitence, the today 's liturgy of the Ash Wednesday, as well as the complete Lent emphasizes the conversion and total revival of the Christian life - primarily through charity, prayer and fasting (penitence).