Short answers, pulled from the story.
The Venetians blocked Maximilian I's journey to Rome, preventing the papal coronation. In 1508 at Trento, he proclaimed himself elected emperor instead, with Pope Julius II later recognising the title. This broke the centuries-old tradition requiring a papal coronation for adoption of the Imperial title.
Maximilian I was known as Coeur d'acier, French for Heart of Steel, a nickname given to him by the Burgundian herald Olivier de la Marche. He was also called der letzte Ritter, the last knight, in the German-speaking world. Historians disagree whether these names praised his courage or criticised his ruthlessness.
Maximilian I married Mary of Burgundy in 1477 and arranged for his son Philip the Handsome to marry Joanna of Castile in 1496, which allowed his grandson Charles V to hold the thrones of both Castile and Aragon. At the First Congress of Vienna in 1515, he arranged marriages that brought Habsburg kingship over Hungary and Bohemia in 1526.
At the end of Maximilian I's reign, the Habsburgs' total debt stood at six million to six and a half million gulden, depending on the source. During his entire reign, he spent around 25 million gulden. Around 70% of his income went to wars, and he was heavily dependent on banking families such as the Fuggers and Welsers of Augsburg.
Maximilian I introduced the Reichskammergericht and the Gemeine Pfennig tax at the 1495 Reichstag at Worms. In 1499, he introduced the Maximilianische Halsgerichtsordnung, the first codified penal law in the German-speaking world. In 1508, he devised the first military code of 23 articles, which remained the universal military code for the Holy Roman Empire until 1642.
Between 1494 and 1510, Maximilian I authorised thirteen expulsions of Jews in exchange for fiscal compensation from local governments. After 1510, his policy shifted significantly, and he showed resistance to further expulsions; historians link the change to his recognition that stable Jewish communities could generate ongoing tax revenues. He appointed Paolo Riccio, a Jewish convert, as his personal physician in 1514, primarily for Riccio's Hebrew skills in translating the Talmud.