The Kingdom of Poland, also informally called Regency Kingdom of Poland , was the state proposed by the Act of November 5 issued by Imperial Germany and Austria-Hungary. It was to be created within the former Russian territory of Congress Poland (however with no defined borders) in 1916 and would exist as a satellite state of Germany. The proposal never gained much support in Germany and in reality was aimed only at gaining a Polish Army for Central Powershttp://books.google.com/books?vid=ISBN0415254051&id=QIdCg9SM3W8C&pg=PA202&lpg=PA202&dq=%22kingdom+of+Poland%22+1916&sig=728Az-b-g4Mkd_gxMD4CZMUH6uE.
The Kingdom of Poland was the Polish state in the years between the coronation of Bolesław I the Brave in 1025 and the death of Bolesław III the Wrymouth in 1138. The legal basis for the existence of this Christian kingdom was established in 1000 during the Congress of Gniezno, when Poland was recognized as the state by Holy Roman Empire and the Pope.
The Kingdom of Poland during period of fragmentation was the Polish state in the years between the death of Bolesław III the Wrymouth in 1138 and the coronation of Władysław I the Elbow-high in 1320.
The Kingdom of Poland of the later Piasts was the Polish state in the years between the coronation of Władysław I the Elbow-high in 1320 and the death of Casimir III in 1370. After two centuries of fragmentation, the period of feudal dissolution ended when Władysław the Elbow-high united the various principalities of the Kingdom of Poland. His son Kazimierz the Great, the last of the Piast dynasty, greatly strengthened the Polish state in both foreign and domestic affairs.
The Kingdom of Poland of the Jagiellons was the Polish state in the years between the death of Casimir III in 1370 and the Union of Lublin in 1569.