On This Day - What happened 2 January

Frederick I, also called Frederick Barbarossa, was crowned Emperor in 1155. He emphasized the "Romanness" of the empire, partly in an attempt to justify the power of the Emperor independent of the (now strengthened) Pope. An imperial assembly at the fields of Roncaglia in 1158 reclaimed imperial rights in reference to Justinian's Corpus Juris Civilis. Imperial rights had been referred to as regalia since the Investiture Controversy but were enumerated for the first time at Roncaglia. This comprehensive list included public roads, tariffs, coining, collecting punitive fees, and the investiture or seating and unseating of office holders. These rights were now explicitly rooted in Roman Law, a far-reaching constitutional act.

With the unsuccessful and bloody Russo-Japanese War (1904–1905) there was unrest in army reserve units. On 2 January 1905, Port Arthur was lost.

On January 2, 1906, Carrier was granted U.S. Patent 808,897 for an Apparatus for Treating Air, the world's first spray-type air conditioning equipment. It was designed to humidify or dehumidify air, heating water for the first function and cooling it for the second.

In 1912, the town of Leipzig, seat of the annual Leipzig Book Fair, the Kingdom of Saxony and the Börsenverein der Deutschen Buchhändler (Association of German booksellers) agreed to found a German National Library in Leipzig. Starting 1 January 1913, all publications in German were systematically collected (including books from Austria and Switzerland).

After the First World War ended, President Woodrow Wilson declared his intention to present a 14-point plan for world peace at the forthcoming Paris Peace Conference. Garvey joined various African-Americans in forming the International League for Darker People, a group which sought to lobby Wilson and the conference to give greater respect to the wishes of people of color; their delegates nevertheless were unable to secure the travel documentation.

On January 2, Guevara entered Havana to take final control of the capital.

On January 2, 1960, Kennedy announced his candidacy for the Democratic presidential nomination.

The inept performance of the South Vietnamese army was exemplified by failed actions such as the Battle of Ap Bac on 2 January 1963, in which a small band of Viet Cong won a battle against a much larger and better-equipped South Vietnamese force, many of whose officers seemed reluctant even to engage in combat.

The first celebration of Black History Month took place at Kent State one year later, from January 2, 1970 – February 28, 1970.

From Chicago, Bundy traveled by train to Ann Arbor, Michigan, where he was present in a local tavern on January 2.

Before the 1980 elections Gandhi approached the then Shahi Imam of Jama Masjid, Syed Abdullah Bukhari and entered into an agreement with him on the basis of 10-point programme to secure the support of the Muslim votes. In the elections held in January, Congress returned to power with a landslide majority.

ARPANET became the technical core of what would become the Internet, and a primary tool in developing the technologies used. The early ARPANET used the Network Control Program (NCP, sometimes Network Control Protocol) rather than TCP/IP. On January 1, 1983, known as flag day, NCP on the ARPANET was replaced by the more flexible and powerful family of TCP/IP protocols, marking the start of the modern Internet.

On 2 January 1990, Mongolian Democratic Union began distributing leaflets calling for a democratic revolution. When the government did not comply with this and later, more aggressive demands, demonstrations occurred.

A new UN-sponsored ceasefire, the fifteenth in just six months, was agreed on January 2, 1992, and came into force the next day.

In their last game under Cruyff, on 2 January 2013, Catalonia drew with Nigeria at the Cornellà-El Prat, 1–1.

Trump also ordered a targeted U.S. airstrike on January 2, 2020, which killed Iranian Major General and IRGC Quds Force commander Qasem Soleimani and Iraqi Popular Mobilization Forces commander Abu Mahdi al-Muhandis, as well as eight other people. Trump publicly threatened to attack Iranian cultural sites if Iran retaliated; such an attack by the U.S. would violate international law.