Bolesław V was born on 21 June 1226 at Stary Korczyn,[1] as the third child and only son of Leszek I the White by his wife Grzymisława, a Rurikid princess of disputed parentage.

The nobility of Kraków wanted the regency to be exercised by Dowager Duchess Grzymisława, jointly with the local voivode and bishop; however, this was contrary to the treaty of mutual inheritance signed in 1217 by Leszek and Władysław III Spindleshanks, under which it was agreed that in the event of the death of one of them, the other would take the government of his domains and custody of his minor children.

[5] Due to the lack of response, Konrad I came to Skaryszew to negotiate with Grzymisława and the local nobility in the first half of March 1228, with regard to assuming the guardianship of his nephew during his minority.

However, a year later Konrad I captured Henry the Bearded and occupied Sieradz-Łęczyca and later Sandomierz, removing Grzymisława from power, despite resistance from the local nobility.

In 1231, with the support of the Gryfici family, Henry obtained the rule over Sandomierz, after Grzymisława (who feared for the future of the inheritance of her infant son) surrendered the regency.

The humiliations to the dowager duchess continued there, including a slap in the face by Konrad I. Henry the Bearded decided to rescue the imprisoned prince and his mother; shortly thereafter Bolesław and Grzymisława managed to escape from the monastery of Sieciechów with the help of Kraków voivode Klement of Ruszcza and Mikołaj Gall, who was in charge of the prisoners.

Both Klement and Mikołaj bribed the guards, who were busy drinking, and did not pay attention to the prisoners, who left the monastery in disguise.

Jan Długosz described the events as follows: For safety reasons, Henry the Bearded hid Bolesław and his mother in the fortress of Skała near the valley of the Prądnik river.

Thanks to Archbishop Pełka, the Treaty of Luchani was signed in August of that year, under which Bolesław received Sandomierz and gave several castles to Henry.

In June 1235, Pope Gregory IX approved the Treaty of Luchani; however, shortly afterwards Konrad invaded Sandomierz, and as a result of this invasion Bolesław lost the district of Radom.

On 9 July of that year, a meeting also took place in Przedbórz between Bolesław and Konrad, at which the Masovian ruler agreed to renounce his claims over Sandomierz.

After the defeat of the Hungarian army at the Battle of the Sajó River two days later (11 April) - where Prince Coloman was seriously injured and died shortly after - Bolesław V and his family (including Salomea, now a widow) fled to Moravia, and then eventually returned to Poland.

After the death of Henry the Pious, his eldest son, Bolesław the Bald, took the title of high duke; however, he did not appear in Kraków, where the government was exercised by Klement of Ruszcza on his behalf.

The lack of funds for war forced Bolesław to take some properties of his wife, Kinga, which were paid only on 2 March 1257 during a meeting at Nowy Korczyn, when she received the district of Stary Sącz.

In 1258 Bolesław the Pious started a long and destructive war against Casimir and his ally Świętopełk (Swantopolk) II for the castellany of Ląd.

On 12 December during a meeting at Przedbórz, Bolesław the Chaste mediated the dispute between Casimir and Siemowit, which ended in a mutual treaty.

In June and July 1253 Polish-Russian forces, including the army of Bolesław the Chaste, rushed to Moravia in support of the Hungarian expedition to Vindelicia (Austria), which was under the rule of King Ottokar II of Bohemia.

The conflict ended with a treaty; at this time, Ottokar (with the help of Bishop Paweł of Kraków) tried to persuade Bolesław the Chaste to join at his side.

In 1260 another conflict erupted between Hungary and Bohemia, when the Hungarian prince Stephen organized a marauding expedition to the Duchy of Carinthia.

In 1271 Bolesław, with the help of Rurikid princes, organized an expedition to the Duchy of Wrocław, because Henry the White was an ally of Bohemia.

In the spring of 1264, Bolesław organized a retaliatory expedition against them, which ended with a victory of the Kraków-Sandomierz troops and the death of the Yotvingian prince Komata.

In November 1259 the Mongols and Ruthenians invaded and destroyed Sandomierz, Lublin and Kraków; Bolesław fled to either Hungary or Sieradz, ruled by Leszek the Black.

After Daniel's death in 1265 a Lithuanian-Russian army invaded and ravaged the Lesser Poland districts of Skaryszew, Tarczek, and Wiślica.

During 1265−66 Bolesław fought against Daniel's son Shvarn and brother Vasilko Romanovich, who helped the Lithuanians in their invasion into Lesser Poland.

At the end of October, Bolesław made a retaliatory expedition against Opole-Racibórz; however, the forces were limited only to destroy specific areas of the duchy.

In 1274 Władysław and Bolesław V the Chaste decided to conclude a peace, under which the Duke of Opole-Racibórz gave up his claims to the throne of Kraków.

On 5 June 1257 during a meeting at Kopernia near Pińczów, he granted the Magdeburg rights to the district of Kraków, and a year later to the city of Nowy Korczyn.

The implementation of the German-styled law led to the rapid economic development in the principality, which experienced losses, up to 75% in population alone, due to Mongol raids.

On 28 August 1252 during a meeting at Oględów, the Duke and his mother Grzymisława granted an immunity privilege to the Bishopric, which guaranteed to the local clergy greater autonomy in economic and judicial matters.

On 17 September 1253, thanks to the joint efforts of Bolesław and the bishop of Kraków, Pope Innocent IV canonized Stanisław (Stanislaus) of Szczepanów.