This article relates to the Kingdom of Poland, also referred to as the Duchy of Poland, which existed between 1025 and 1103 AD, although a recognisable Polish state had existed previously.
The basis for the development of a Polish state was laid by the Piast dynasty, which was preeminent since the early 10th century AD.
Duke Mieszko I's conversion to Christianity, along with his pledge of loyalty to Otto I, Holy Roman Emperor, paved the way for a country later called Poland to become a member of the family of Christian kingdoms.
In 1000, during the Congress of Gniezno, Duke Boleslaw I was recognized as co-operator by the Holy Roman Empire and the Pope.
In 1025, Duke Boleslaus I the Brave crowned himself King of Poland, the appointment accepted by the Pope. This initial Polish kingdom ended within one year, upon the death of Boleslaw I. He was followed for many years by dukes ruling Poland, not Kings.
In 1082, Duke Wladyslaw set out on a campaign to unify his deeply divided duchy.
One of his aims was to gather enough support to effectively declare himself King of Poland, with the support of the majority of his population. He managed, through gruelling campaigning, to gain the support of the majority of Polish nobility. This lead to him being able to publicly declare himself 'King of Poland' by June 1084, with a grand ceremony marking the official proclamation.
The Kingdom of Poland under Wladyslaw I gained Papal recognition by February 1085, and reluctant recognition from the Holy Roman Empire some time in 1086, with the recognition of most other European nations following soon after.
The Kingdom grew massively in 1089, with the annexation of vast stretches of territory including Moldavia, and again in 1094, with the annexation of Pomerania. These expansions were a result of campaigns initiated by Wladyslaw in an attempt to realise his vision of a Greater Polish Kingdom, which lead to the development of New Poland.
Incorporation into New Poland
Following the annexation of Prussia in 1103/04, Poland was incorporated into the Empire of New Poland, as the central nucleus of the new state.
Poland, and Poles, were the core of New Poland and the dominant party. New Poland was still referred to as 'The Kingdom of Poland' in an official sense for the next fifty or so years, and the monarch is still referred to as 'King of Poland'.
However, a local Duchy was established within New Poland, the title being 'Duke of Lesser Poland' which leads to confusion over the status of Poland within New Poland.