[1] Charles II, who was the youngest son of Ferdinand I, Holy Roman Emperor, had inherited the Inner Austrian provinces—Styria, Carinthia, Carniola, Gorizia, Fiume, Trieste and parts of Istria and Friuli—from his father in 1564.

[4] They were devout Catholics, but Charles II had to grant concessions to his Lutheran subjects in 1572 and 1578 to secure the predominantly Protestant nobles and burghers' financial support for the establishment of a new defense system against the Ottoman Empire.

[29] A former Jesuit student, Lorenz Sonnabenter, whom Ferdinand had sent to a parish in Graz, made a formal complaint against the local Lutheran pastors on 22 August, accusing them of unlawfully interfering in his office.

[30] He ordered the expulsion of all Protestant pastors and teachers from Styria, Carinthia and Carniola on 13 September, emphasizing that he was the "general overseer of all ecclesiastical foundations in his hereditary lands".

[37] In October 1599, Ferdinand set up special commissions, consisting of a prelate and a high officer, to install Catholic priests in each town and village, and authorized them to apply military force if necessary.

[51][52] At their meeting in Linz in April 1606, the four archdukes concluded that the emperor was incompetent and decided to replace him with Matthias in Bohemia, Hungary and Upper and Lower Austria.

[54] The resulting agreement was included in the Treaty of Vienna, which granted religious freedom to Hungarian Protestants and prescribed the election of a palatine (or royal deputy) in Hungary on 23 June 1606.

[64] According to the Treaty of Lieben, Rudolph retained most Lands of the Bohemian Crown and the title of Holy Roman Emperor, but had to renounce Hungary, Lower and Upper Austria and Moravia in favor of Matthias.

[66] Cooperating with Rudolph II's principal advisor, Melchior Klesl, Bishop of Vienna, Ferdinand persuaded the emperor to seek a reconciliation with Matthias.

[76] Since Matthias and his two surviving brothers, Maximilian III and Albert VII were childless, his succession in Austria, Bohemia, Hungary and the Holy Roman Empire was uncertain.

[83] Ferdinand sought assistance from Spain and the Venetians received support from the Dutch and English, but neither side could achieve a decisive victory in the Uskok War.

[83] The Venetians abandoned the Siege of Gradisca on 22 September, but peace was restored only in early 1618, after Ferdinand agreed to resettle the Uskoks from the coastline and ordered the destruction of their ships.

[106][111] Since only 300 soldiers were staying in the town, Ferdinand sent envoys to his commander at Krems, Henri Duval, Count of Dampierre and entered into negotiations with the Upper Austrian Protestants about their demands.

[109] After Ferdinand's general, Charles Bonaventure de Longueval, 2nd Count of Bucquoy, defeated the Bohemian rebels in the Battle of Sablat, Thurn lifted the siege on 12 June.

[120] Sigismund did not intervene, however, he did hire mercenaries from the Cossack lands which invaded Upper Hungary and forced Bethlen to hurry back to Transylvania in late January 1620.

[120] After his new confessor, the Jesuit Martin Becanus, assured him that he could grant concessions to the Protestants to secure their loyalty, Ferdinand confirmed the Lutherans' right to practise their religion in Lower Austria, save the towns on 8 July 1620.

[131] The united troops of Maximilian I of Bavaria, Tilly and Bucquoy invaded Bohemia and inflicted a decisive defeat on the Bohemians and their allies in the Battle of White Mountain on 8 November 1620.

[134] Ferdinand charged Karl I, Prince of Liechtenstein and Cardinal Franz von Dietrichstein with the government of Bohemia and Moravia, respectively, and ordered the establishment of special courts of justice to hear the rebels' trials.

[138] After lengthy negotiations, Bethlen renounced the title of king of Hungary, after Ferdinand ceded him seven Hungarian counties and two Silesian duchies in the Peace of Nikolsburg on 31 December 1621.

[141] The liberal issue of the new currency caused "the western's worlds first financial crisis",[142] featured by inflation, famine and other symptoms of economic and social disruption.

[158] Maximilian I of Bavaria, who still held Upper Austria in pledge, proposed a cautious approach in the province, but Ferdinand ordered the expulsion of all Protestant pastors and teachers on 4 October.

[154] Ferdinand also achieved the election of a Catholic magnate, Count Miklós Esterházy, as the new palatine with the support of the Archbishop of Esztergom, Cardinal Péter Pázmány.

[165] In the same month, Maximilian ordered Tilly to move his troops into Lower Saxony, and Wallenstein invaded the Archbishopric of Magdeburg and the Bishopric of Halberstadt, but a fierce rivalry between the two commanders prevented them from continuing the military campaign.

[167] Taking advantage of the peasant revolt in Upper Austria, Christian IV departed from his headquarters in Wolfenbüttel, but Tilly routed his troops in the Battle of Lutter on 26 August 1626.

He did not wish to uphold the religious liberties granted by the Letter of Majesty signed by the previous emperor, Rudolph II, which had guaranteed freedom of religion to the nobles and cities.

On 8 November 1620 his troops, led by the Flemish general Johann Tserclaes, Count of Tilly, smashed the rebels of Frederick V, who had been elected as rival King in 1619.

After Frederick's flight to the Netherlands, Ferdinand ordered a massive effort to bring about re-conversion to Catholicism in Bohemia and Austria, causing Protestantism there to nearly disappear in the following decades, and reducing the Diet's power.

Some historians directly blame Ferdinand for the large civilian loss of life in the Sack of Magdeburg in 1631: he had instructed Tilly to enforce the edict of Restitution upon the Electorate of Saxony, his orders causing the Belgian general to move the Catholic armies east, ultimately to Leipzig, where they suffered their first substantial defeat at the hands of Adolphus' Swedes in the First Battle of Breitenfeld (1631).

Wallenstein was recalled, being able to muster an army in only a week, and immediately staked a tactical, if not strategic, victory at the September Battle of Fürth, quickly followed by his forces expelling the Swedes from Bohemia.

; Archduke of Austria, Duke of Burgundy, Brabant, Styria, Carinthia, Carniola, Margrave of Moravia, Duke of Luxemburg, of the Upper and Lower Silesia, of Württemberg and Teck, Prince of Swabia, Prince of Transylvania, Count of Habsburg, Tyrol, Kyburg and Gorizia, Landgrave of Alsace, Marquess of the Holy Roman Empire, Burgovia, the Enns, the Upper and Lower Lusatia, Lord of the Marquisate of Slavonia, of Port Naon and Salines, etc.