The Colt is a singular gun made by Samuel Colt in 1835 for a hunter at the time. It has supernatural powers: when used with the similarly supernatural bullets made specially for it, the gun can kill anything.1.20
Colt Gun PoD
Invented by Samuel Colt, a gun named after its inventor “Colt”, and after its revolving cylinder. Before the Colt revolver, only one and two-barrel flintlock pistols had been invented for hand held use. Colt revolvers were all based on cap-and-ball technology until the Smith and Wesson license on the bored-through cylinder (bought from Rollin White) expired around 1869. PoD
See also Weapons Box
Samuel Colt (1814-1862) was the inventor of the Colt revolver, and founder of the Colt Firearms company. See Wikipedia entry for further info.
It should be noted that Samuel Colt spent 1835 in England and France, securing the first patent on his revolving-breech pistol. He returned home and obtained an American patent in 1836.
Appearances and Use in Episodes
The Colt in "Supernatural"
It first appears in Season 1 of Supernatural when Daniel Elkins is killed, leaving John a note saying that he had it (along with the five remaining bullets) in his possession.1.20 After retrieving the Colt from the vampires who killed Elkins and looted his property, the Winchesters attempt to use it to kill Azazel but fail, using several bullets along the way (John kills a vampire in 1.20, Dean a demon in 1.22, Sam in an attempt to kill Azazel in 1.21 and again in 1.22).
In the first episode of Season 2, John trades the Colt (and his soul) in a deal with Azazel for Dean's life. The Colt doesn't appear again until 2.21, when Azazel gives it to Jake Talley in order to open the Devil's Gate in Wyoming. In the chaos that ensues, Dean gets possession of the Colt again and uses the last bullet to kill Azazel.2.22
In the early episodes of Season 3, we see Bobby working on the Colt - trying to figure out how it works. He succeeds with the help of Ruby. At the end of 3.04, the Colt is in Sam's possession.
The Colt used in Supernatural has some special "features":
non timebo mala translates to "I will fear no evil" from Latin, and is possibly a reference to Psalm 23.
Pentagram: See Pentagram
Use of the Colt
How Samuel Colt's five remaining bullets are used
Legend of The Colt: Additional Definition
"The Battle of the Alamo was a 19th-century battle between the Republic of Mexico and the rebel Texan forces during the latter's fight for independence - the Texas Revolution . It took place at the Alamo mission in San Antonio, Texas (then known as "San Antonio de Béxar") in February and March of 1836". (Source: Wikipedia)
History of Conflicts
Although most people automatically think of the famous battle that occurred in 1836 when the Alamo is mentioned there is a history of minor battles that occurred at the Alamo. The Alamo has a long and bloody history beginning in the mid to late 1700's.
In October of 1835 one of many battles occurred between residents of Gonzales and the Mexican troops that occupied the Alamo at the time. This skirmish led to Santa Anna sending in troops under Martin Perfecto de Cós to San Antonio. This was only one of many smaller battles over the course of October, November, and December of 1835 that eventually led to the famous battle that occurred in February and March of 1836.
For more information about the history/timeline of the Alamo check out the Daughters of the Republic of Texas website. They include a detailed history of the Alamo and all its battles.
The battle in 1835 is usually referred to as the Siege of Béxar, was the first battle for the occupation of the Alamo, in which the Texans took possession from the Mexican Governmental troops. It took place between October 12 and December 11th, 1835. On December 7th, the Texans had all of their artillery in place and began their assault on the Alamo. The flag of surrender was sent out from the Alamo to the Texan army on December 9th. So a good guess as to the exact 'night those men died' would be December 8th, 1835.
(sources Siege of Béxar (Bejar) - Wikipedia Siege of Béxar (Bejar) - Wikipedia and Siege & Battle of Béxar from the Dairy of Samuel Maverick)
"Comet Halley ... more generally known as Halley's Comet after Edmond Halley, is a comet that can be seen every 75-76 years. It is the most famous of all periodic comets, even though in every century many comets appear brighter and more spectacular. Halley's comet last appeared in the inner Solar System in 1986, and will next appear in the summer of 2061." (Source: Wikipedia)
In 1835, it achieved perihelion on 16 November, but would have been visible from Earth for several weeks before and after.
The number 13
In Western culture, the number 13 is generally considered to be unlucky. However, this has not always been the case. See this article on 'triskaidekaphobia' (fear of the number 13) for a various uses and readings of the number 13 in a range of different cultures, religions and mythologies.
When speculating you might also be interested in the decoding of the name Winchester.