Sigismund I the Old (Polish: Zygmunt I Stary, Lithuanian: Žygimantas I Senasis; 1 January 1467 – 1 April 1548) was King of Poland and Grand Duke of Lithuania from 1506 until his death in 1548.

Sigismund I was a member of the Jagiellonian dynasty, the son of Casimir IV and younger brother of Kings John I Albert and Alexander I Jagiellon.

When Casimir died, the Polish-Lithuanian realm was divided between the remaining two older sons, with John Albert being crowned King of Poland, and Alexander as Grand Duke of Lithuania.

A capable monarch and a patron of arts, Sigismund established Polish rule over Ducal Prussia and annexed the Duchy of Mazovia with Warsaw, while retaining the nation's wealth and prominence in the region.

Sigismund and his commander Jan Amor Tarnowski also defeated Moldavia at Obertyn in 1531, and Muscovy in 1535, thereby strengthening the country's eastern borders.

His 42-year reign was further marked by decisive contributions to Polish architecture, cuisine, language, and customs, especially at the behest of his second wife, the Italian-born Bona Sforza.

Finally, his eldest brother Vladislaus II, King of Bohemia and Hungary, granted him the duchies of Głogów (1499) and Opava (1501), and in 1504 Sigismund became governor of Silesia and Lower Lusatia.

Eventually, during his reign, Sigismund benefited from the advice of the local nobility, competent ministers in charge of the royal judiciary system, and the wealthy influential treasurers of Kraków.

Sigismund successfully organised the agricultural economy, looked after the development of the royal cities and recovered numerous goods of the treasury belonging to the crown that were under lien.

During the financial activities, the King received full support of his wife, Queen Bona, who aimed to expand the royal estates by purchasing and improving economic efficiency.

[10] At the start of his reign, King Sigismund I the Old inherited a Kingdom of Poland with a century-long tradition of liberties of the nobility, confirmed in numerous privileges.

Supported by his Italian consort Bona Sforza, he began buying up land and issue agriculture reformas to enlarge the royal treasury.

Sigismund rejected most of their demands, while accepting the principle of Incompatibilitas the following year and agreeing not to force the election of the future king in vivente rege.

Further tensions escalated when Vasili also discovered that Sigismund was bribing Khan Meñli I Giray to attack the Grand Duchy of Moscow.

[12] In December 1512, Muscovite forces marched into the Grand Duchy of Lithuania seeking to capture Smolensk, a major trading center between Russia and Europe.

In 1512, Grand Hetman of Lithuania, Konstanty Ostrogski, ransacked the region of Severia and vanquished a Russian force of approximately 6,000 men.

On 8 September 1514, Muscovy suffered a major defeat at the Battle of Orsha, which prevented the Russians to place all the former Kievan Rus' lands under their lordship.

A letter sent to Rome stated that "Muscovites are not Christians; they are cruel and barbaric; they are Asians and not Europeans; they are in league with Turks and the Tatars to destroy Christendom".

Through this double marriage contract, Bohemia and Hungary passed to the House of Habsburg in 1526, on the death of Sigismund's nephew, Louis II, who led his forces against Suleiman the Magnificent of the Ottoman Empire in the disastrous Battle of Mohács.

Worried about the growing ties between the Habsburgs and Russia, in 1524 Sigismund signed a Franco-Polish alliance with King Francis I of France to avoid a possible war on two fronts.

[20] Francis I himself was looking for allies in Central Europe to curtail the increasing power of Habsburg Emperor Charles V, whose realms were labelled "the empire on which the sun never sets".

[22][23] The accusations were so pervasive and rampant that Sigismund ordered an investigation, as a result of which a special edict was declared on 9 February 1528 confirming that the Masovian princes died naturally or due to related illness.

[24] In other matters of policy, Sigismund sought peaceful coexistence with the Khanate of Crimea, but was unable to completely end border skirmishes.

[26] Previously, the Second Peace of Thorn (1466) placed the Teutonic Order under Polish suzerainty and interfered with German interests in Livonia, Pomerania, Warmia and Masuria.

Among the illustrious figures that guested or lived in Poland at the time were Bartholommeo Berecci, Francesco Fiorentino, Santi and Mateo Gucci, Bernardo Morando, Giovanni Battista di Quadro and Hans Dürer.

Situated on a hill overlooking Old Town, the fortified residence was extensively reconstructed in the Renaissance style and to the personal needs of the royal family.

He was succeeded by his only legitimate son, Sigismund II Augustus, who became the last Jagiellon king of Poland and Grand Duke of Lithuania.