Bezprym is the only child of Boleslaw I the Brave born from his second marriage with an unknown Hungarian princess, who, in older literature, was identified as Judith, daughter of Géza, Grand Duke of Hungary.

Though opinions vary about the identity of Boleslaw’s second wife, there is a number of researchers still support the hypothesis of her being the daughter of Géza.

The marriage of Bezprym’s parents had ended soon after his birth, probably because of the deterioration in political relations between Poland and Hungary.

Bezprym's mother had been repudiated and sent away, although probably she remained in Poland and died soon afterwards.

Shortly after Boleslaw’s divorce, he had remarried with Emnilda, who has borne him five children.

The eldest son of this union, the future Mieszko II Lambert, was born in 990.

Almost nothing is known about Bezprym's first years of life in contrast with his half-brother Mieszko II, whose youth is fully described in several contemporary sources.

This probably shows that his father disliked him and considered Mieszko II as his successor since his birth, which was already confirmed by Boleslaw’s later political activity.

Bezprym was destined to a Church career, a fact demonstrated in the Vita of St. Saint Romuald, a hermit from Ravenna.

There it is stated that in one of the hermitages resided a son of a Polish Duke, who in 1001 gave him a horse.

According to modern historians, this Polish prince could only be Bezprym.

In earlier historiography, it was theorized that the Polish prince who lived in the hermitage of Ravenna was Lambert, son of Mieszko I or an unknown son of Boleslaw from his first marriage with the daughter of Rikdag, Margrave of Meissen.

It is possible that he was in Hungary and there he was appointed head of Veszprém and Zala county.

In this case the name "Veszprém" originated from his name.

This hypothesis proposed by a Hungarian researcher, is not accepted by Polish historians.

It is also probable that Bezprym was present at the coronation of his father as King of Poland in Gniezno Cathedral on April 25, 1025.

Probably after Mieszko II took control over the government of Poland, both Bezprym and his youngest half-brother Otto resided in Poland for a short time.

However, Mieszko had soon expelled Bezprym from the country.

He probably does the same with Otto in 1030, when he discovers that they are conspiring against him with the help of Emperor Conrad II.

Bezprym had taken refuge in Kievan Rus and probably used the weakened position of Mieszko II as an excuse to gain the alliance of the Rurikid rulers Yaroslav I the Wise and Mstislav.

In 1031, while Mieszko is defending the western border from the German expedition of Conrad II, Bezprym and the Kievan forces enter into Poland.

Busy defending Lusatia and consequently unable to repel the Kievan attack, Mieszko II is forced to escape to Bohemia.

Yaroslav annexes Red Ruthenia to his domains and Bezprym ascends to the Polish throne.

Having degraded the power structure in Poland, Bezprym loses his authority shortly after taking power, and is forced to surrender the royal crown and regalia to the Emperor.

Thus, he resigns from the royal title and accepts the primacy of his western neighbor.

The crown and regalia are personally delivered by Mieszko's wife, Queen Richeza, who together with her children Casimir, Ryksa and Gertruda, leaves the country in 1031 for the court of Emperor Conrad II, where the deposed Queen is received with all honors and allowed to continuous use of the royal title.

The departure of Richeza, and especially of her son, is extremely beneficial for Bezprym, because this eliminates (at least temporarily) a possible pretender to the throne.

Mieszko II isn't considered too dangerous at this time, since he is imprisoned and castrated in Bohemia by orders of Duke Oldrich.

This is a retaliation for Boleslaw I Chrobry’s blinding of Duke Boleslaus III the Red, Oldřich's brother, thirty years before.

Mieszko and his wife will never reunite again; according to some sources they were either officially divorced or only separated.

It is possible that the new rule of Duke Bezprym is attractive to the Polish population.

However, there probably remains a large group of supporters of the former ruler.

It is believed that Bezprym began his bloody persecution against them shortly after he began his government.

Many representatives of the Polish social elite are forced to flee as a result.

According to sources, some of them took refuge in Masovia.

Perhaps among the victims of the repression, there were two bishops, whose date of death is recorded in 1032 in the Chronicles of the Chapter of Kraków: Roman and Lambert.

The brutal fight with the opposition could have led to the above-mentioned Pagan Reaction, however it was probably instigated by discontent against the power of the Church and with the state apparatus.

Contemporary historiography places the riots in 1031–1032, during the reign of Bezprym.

The reaction isn't only of a religious background, but social.

It is primarily a reflection of the economic state caused by the aggressive policy of Boleslaw I the Brave and less successful rule of Mieszko II.

The defeat in battle in the west during that period has cut off the basic source of livelihood of the Polish troops, who are forced to loot the western lands.

As a result, the cost of maintaining the existence of an extensive army is probably too much for the population.

In addition, the devastating incursions of foreign troops is another cause of dissatisfaction among the citizenry.

The rule of Bezprym is extremely cruel and short.

According to the Chronicles of Hildesheim, he was murdered by his own men no later than spring of 1032.

Probably the instigators of his death were his half-brothers, although the main conspirator was Otto, who remains free in Germany.

The place of his burial is unknown.

As a result of Bezprym's rule, the Polish state has been substantially weakened, and the Polish throne remains vacant.

Mieszko II is still imprisoned in Bohemia and Otto probably in Germany.

German sources report that the Empero organized an expedition in order to invade Poland.

It is unknown what happened after this, but certainly Mieszko II was released by Duke Oldrich and he could return to the country.

After his recent opponent regains the power, the Emperor immediately reacts and begins the preparations for the expedition against Poland.

Mieszko II isn't prepared for the confrontation, so he uses his influence in the German court in order to resolve the conflict.