The story of these panzers begins in 1930s Czechoslovakia. The Czech army needed a new tank for its arsenal, so designers went to work on the tank that would eventually become the LT-35. It was apparently an unreliable vehicle, and it was to be replaced by another vehicle, the LT-38, which was armed with one 37mm antitank gun and two machine guns. However, Germany intervened by taking over Czechoslovakia. Instead of discarding the vehicles the Germans kept them and even continued the production of LT-38s( now Panzer 38t) until 1942! Both vehicles saw extensive service in the Polish, French and early Russian campaigns. Both were phased out in 1942-43 due to inadequate armor and firepower.
NOTE: Although the Panzer 38t was phased out of service, the Jagdpanzer version went on to serve after world war two, and the Swiss only stopped using them in 1970! That vehicle will be described in a later post.