The foundational history of the Max Planck Society's research institutions in the eastern German states began on July 3, 1990 — just two days after the State Treaty on the Monetary, Economic, and Social Union of the two German states came into force. The first Institute in Saxony, the Max Planck Institute for Physics of Complex Systems in Dresden, started its work in the summer of 1993. Five more Institutes followed suit. Reflecting on this time, the then President of Max Planck Society, Hubert Markl, wrote in the late 1990s: "Creating such innovation across various scientific areas in the Max Planck Society was not only a unique challenge, but also an exciting experience."