Mieszko II Obese the (in Polish Mieszko II Otyły ), from the dynasty of the Piasts, was born towards 1220 and deceased the October 18th or the October 22nd 1246. He is the oldest son of Casimir Ier d' Opole.

He was the duke of Opole and Racibórz of 1230 with 1246 (he actually controlled starting from 1239).

With died of his/her father in 1230, it is too young to reign. He and its family is taken under the protection of Henri Ier Bearded the. His/her mother ensures regency and continues the policy of close cooperation with the Église, installation by Casimir d' Opole. In 1233, undoubtedly with the agreement of Henri Ier the Bearded one, it obtains a bubble Pape Gregoire IX by which he places it, like his/her children, under the protection of the Archevêché of Gniezno and the évêché S of Wrocław and Olomouc. The following year, Henri Ier takes the control of the duchy of Opole, giving in exchange to the family of Casimir Ier d' Opole the areas of Kalisz and Wieluń. However, it does not call in question the right of wire of Casimir to reign about this duchy. In 1238, following the death of Henri Ier the Bearded one, his son Henri II the Piles takes again the duchy of Opole and of Racibórz under its protection but must very quickly recognize the right of Mieszko to control the duchy of his/her father.

As of the beginning 1239, Miesko II the Obese one takes the succession of his/her father. One of its first political acts is its marriage with Judith, the girl of Conrad Ier de Mazovie. This marriage enables him to be less dependant on Henri II the Piles. Whereas he embraced the capacity in the duchy of Opole and Racibórz, his/her mother and her young brother Ladislas d' Opole continue to reign on the duchy of Kalisz, under the protection of the duke of Wrocław.

At the beginning 1241, its reign is brutally disturbed by the Mongolian invasion . Contrary to the duke of Sandomierz Boleslas V Modest the, Mieszko does not give up its duchy with the invaders and fact face. The chance smiles to him at the beginning. In March 1241, it attacks by surprised Mongolian detachments which were on the point of crossing the Oder, which left more time to Henri II the Piles to prepare with the battle against the Mongols. Having delayed the Mongolian projection, it did not take the risk to face large horde and was folded up on Legnica. The Bataille of Legnica ended in the defeat of Henri II. One of the principal explanations to this defeat is the escape of Mieszko and its army at one crucial moment of the battle.

As of May 1241, Mieszko reappears in its duchy and starts to rebuild the territories devastated by the Mongols. In 1241, Ladislas, the younger brother reaches the age of his majority, but does not assert part of the territory of his/her brother, being satisfied to reign on the duchy of Kalisz. The death of Henri II changes the situation, its successor wanting to recover Kalisz. In 1244, Ladislas gives up Kalisz to preserve only Wieluń (until in 1249).

In 1243, Mieszko II supports militarily his/her father-in-law Conrad Ier de Mazovie in its fight to preserve the throne of Cracow. They are crushed by Boleslas V Modest the.

During all its reign, Mieszko tested, without many positive tests, to continue the economic development policy initiated by his/her father.

Mieszko II the Obese one had a very fragile health. It is deceased the October 18th or the October 22nd 1246, without leaving descent. It bequeathed its possessions to his young Ladislas brother.