What happened 1800 AD

It was not until mass Irish and Scottish immigration in the 19th century that Halloween became a major holiday in North America.

In the spring of 1800, Napoleon and his troops crossed the Swiss Alps into Italy, aiming to surprise the Austrian armies that had reoccupied the peninsula when Napoleon was still in Egypt.

In 1800, he was sent to Spain to follow his military studies in Madrid, where he remained until 1802.

Banneker kept a series of journals that contained his notebooks for astronomical observations, his diary and accounts of his dreams. The journals, only one of which escaped a fire on the day of his funeral, additionally contained a number of mathematical calculations and puzzles. The surviving journal described in April 1800 Banneker's recollections of the 1749, 1766 and 1783 emergencies of Brood X of the seventeen-year periodical cicada, Magicicada septendecim, and stated, "... they may be expected again in they year 1800 which is Seventeen Since their third appearance to me." The journal also recorded Banneker's observations on the hives and behavior of honey bees.

While one French army approached from the north, the Austrians were busy with another stationed in Genoa, which was besieged by a substantial force. The fierce resistance of this French army, under André Masséna, gave the northern force some time to carry out their operations with little interference.

The Library of Congress was subsequently established April 24, 1800 when President John Adams signed an act of Congress providing for the transfer of the seat of government from Philadelphia to the new capital city of Washington. Part of the legislation appropriated $5,000 "for the purchase of such books as may be necessary for the use of Congress ... and for fitting up a suitable apartment for containing them". Books were ordered from London, and the collection consisted of 740 books and three maps which were housed in the new United States Capitol.

The Library of Congress was established on 24 April 1800, when president John Adams signed an act of Congress providing for the transfer of the seat of government from Philadelphia to the new capital city of Washington.

After spending several days looking for each other, the two armies collided at the Battle of Marengo on 14 June. General Melas had a numerical advantage, fielding about 30,000 Austrian soldiers while Napoleon commanded 24,000 French troops. The Battle of Marengo was fought on 14 June 1800 between French forces under the First Consul Napoleon Bonaparte and Austrian forces near the city of Alessandria, in Piedmont, Italy. Late in the afternoon, a full division under Louis Desaix arrived on the field and reversed the tide of the battle. A series of artillery barrages and cavalry charges decimated the Austrian army, which fled over the Bormida River back to Alessandria, leaving behind 14,000 casualties.

The Austrian army agreed to abandon Northern Italy once more with the Convention of Alessandria, which granted them safe passage to friendly soil in exchange for their fortresses throughout the region.

The Conspiration des poignards (Daggers Conspiracy) or Complot de l'Opéra (Opera Plot) was an alleged assassination attempt against Napoleon Bonaparte. The members of the plot were not clearly established. Authorities at the time presented it as an assassination attempt on Napoleon at the exit of the Paris operahouse on 18 vendémiaire year IX (10 October 1800), which was prevented by the police force of Joseph Fouché. However, this version was questioned very early on.

Bonaparte gave orders to his general Moreau to strike Austria once more. Moreau and the French swept through Bavaria and scored an overwhelming victory at Hohenlinden in December 1800.

The Plot of the rue Saint-Nicaise, also known as the Machine infernale plot, was an assassination attempt on the life of the First Consul of France, Napoleon Bonaparte, in Paris on 24 December 1800. It followed the conspiration des poignards of 10 October 1800, and was one of many Royalist and Catholic plots. Though Napoleon and his wife Josephine narrowly escaped the attempt, five people were killed and twenty-six others were injured.