Short answers, pulled from the story.
The dagger buried with Tutankhamun in 1323 BC was forged from meteoric iron. This material contained 10% nickel and 0.6% cobalt, matching the composition of a meteorite found in the region. It was valued as highly as gold in ancient Egypt.
The Roman pugio became a standard issue for legionaries after being adopted directly from the Iberian tribes of southern Spain and southwestern France. This double-edged iron thrusting dagger featured a triangular blade designed for close-quarters combat. It persisted through centuries of Roman expansion as a reliable weapon for desperate moments.
The stiletto evolved as a narrow, needle-like blade without cutting edges to thrust into gaps of maille and plate armor. This design targeted eye slits of helmets or joints of armor using a reverse grip known as the icepick grip. The shift focused solely on the ability to penetrate steel rather than raw cutting power.
The baselard, daga, puñal, poniard, and dirk were popular civilian weapons in 17th and 18th century Spain and England. The baselard was a larger dagger with a cross-hilt often worn as a fashion accessory. These daggers were sometimes so oversized that they were satirized as symbols of identity and social standing.
William E. Fairbairn and Eric A. Sykes designed the Fairbairn Sykes fighting knife during World War II. They developed the weapon based on their experiences in the Shanghai Municipal Police Force. The dagger was issued to British Commandos and became a symbol of daring and skill required for special operations.
The assassination of Julius Caesar in 44 BC cemented the dagger's association with deception and treachery. A group of senators used daggers to strike down the Roman dictator, establishing the weapon as a symbol of betrayal. This event led to the phrase cloak and dagger describing a deceitful or traitorous attack.