Today in Lithuania, the day of the establishment of the modern nation-state is celebrated on 16 February. It is well known that the origins of this celebration go back to the period before the Second World War. However, historians have stated for some time now that in the 1920s, in addition to 16 February, there was another day that was also known as the National Day: 15 May. An attempt is made here for the first time to look at the two celebrations as alternatives set by political competition. The author seeks to find explanations why some politicians wanted to see 15 May as a counterbalance to 16 February, and examines whether this was influenced by their different experiences and different views as to what constituted the starting point of the independent Lithuanian state.