The modern design of the flag of Switzerland was introduced as the official national flag after 1950 .
Use of the white cross as a military ensign ( attached to the cantonal flags in the form of strips of linen ) has been used in the Old Swiss Confederacy since the 14th century , but the modern design of a white cross suspended in a square red field was introduced only during the Napoleonic period , first used in 1800 during the Hundred Days by general Niklaus Franz von Bachmann , and was introduced as the official national flag in 1999.