[1][2] Farkas Bethlen was a Hungarian nobleman who lost his ancestral estate, Iktár (now Ictar-Budinț in Romania), due to the Ottoman occupation of the central territories of the Kingdom of Hungary.

[4] Gabriel's court historian, Gáspár Bojti Veres, described Lázár as a "grumpy and fierce" soldier who did not care much about their formal education.

[6] Modern historians try to reconstruct the major events of Gabriel's youth based on sources (primarily memoirs and letters) completed decades later, because only two documents written between 1593 and 1602 mentioned him.

[8] Based on these sources, modern historians assume that Bocskai boosted Gabriel's career in Sigismund Báthory's court,[9][2] but no contemporaneous document mentioned his presence in the prince's retinue.

[6] Sigismund Báthory joined the anti-Ottoman Holy League of Pope Clement VIII and broke into Ottoman territory in the summer of 1595.

[10] According to historian József Barcza, Gabriel gained his first direct experience of warfare fighting against the Ottomans in the Battle of Giurgiu in Wallachia in 1595.

[11] After a series of Ottoman victories, Báthory abdicated in return for the Silesian duchies of Opole and Racibórz in 1597, enabling the commissioners of the Holy Roman Emperor, Rudolph (who was also king of Royal Hungary) to take possession of Transylvania.

[11][15] Historian József Barcza also says, Gabriel must have realized around that time that the Habsburg monarchs were unable to defend Transylvania against the Ottomans.

[13] Michael the Brave, Prince of Wallachia, broke into Transylvania and defeated Andrew in the Battle of Sellenberk (at present-day Șelimbăr in Romania) on 8 October 1599.

[17] During the following years, Transylvania was regularly pillaged both by Basta's unpaid mercenaries, and by Ottoman and Crimean Tatar troops.

[6] Their agreement also refers to the anarchic situation, mentioning the possibility that "either pagan or some godless prince or the governor" would seize Gabriel's property.

[16] Sigismund Báthory (who had again returned to Transylvania) granted Gabriel and his brother landed property in Arad County in June 1602.

[22] After royal troops attacked the refugees' camp near Temesvár on 13 September 1604, rumours about the capture of a secret correspondence between Bethlen and Bocskai began circulating.

[18] Fearing reprisals, Bocskai withdrew to his fortress at Sólyomkő (now Şoimeni in Romania) and make preparations to resist.

In 1613, after Báthory was murdered, the Ottomans installed Bethlen as Prince of Transylvania and this was endorsed on 13 October 1613 by the Transylvanian Diet at Kolozsvár (Cluj-Napoca).

In September 1619, after refusing to convert to Calvinism, the Jesuits Marko Križevcanin, Stephen Pongracz and Melchior Grodeczki were martyred under Bethlen's authority.

After defeating the Czechs on 8 November 1620 at the Battle of White Mountain, Ferdinand II persecuted the Protestant nobility of Bohemia.

Bethlen renounced his royal title on the condition that Hungarian Protestants were given religious freedoms and were included in a general diet within six months.

Bethlen was given the title of Imperial Prince (of Hungarian Transylvania), seven counties around the Upper Tisza River and the fortresses of Tokaj, Munkács (now Mukacheve), and Ecsed (Nagyecsed), and a duchy in Silesia.

After the second campaign, Bethlen offered as rapprochement to the court of Vienna an alliance against the Ottomans and his marriage to an archduchess of Austria, but Ferdinand rejected his overtures.