The Protestant Union or League of Evangelical Union (also known as the Evangelical Union or Union of Auhausen) was a coalition of Protestant German states that was formed in 1608 to defend the rights, lands and person of each member. The Protestant Union was weakened from the start by the non-participation of several powerful Protestant rulers, such as the Elector of Saxony. The Union was also beset by internal strife between its Lutheran and Calvinist members.