The Elongated Man and the Silver Age Timeline!, pt. II: Classic

After a drastic change in censorship (courtesy of McCthyism and, specifically, one Fredric Wertham, of Seduction of the Innocent fame), the target audience became younger kids and what they were allowed to see; consequently stories were simpler and threats more unrealistic. 

During the most classic years of the Silver Age, DC merged the concept of urban superheroes with double identities that was popular in the Golden Age with sci-fi themes that were common in the 1950s. The Martian Manhunter is the first and most obvious example of this. This time, instead of magic, fire-weapons and gimmicks, the new characters used powers based on "super science".  
Additionally, some of the most notorious characters were new versions of old golden age characters with different identities: the Flash, Green Lantern, The Atom, Hawkman, Clayface, Robotman, the Turtle, Red Tornado and Zatanna (daughter of Zatara). They lived in a different reality form the originals, so, the new Flash is often considered the starting point. However, a number of characters that appeared before Flash were kept as part of that continuity, like Superman, Batman,Wonder Woman and Aquaman, all of whom kept their series after the golden age, or like Phantom Stranger and the Martian Manhunter, who were created few years before the scarlet speedster.Most of the superheroes of these times were basically the same guy: a tall, classically handsome, square-jawed, white, muscular, single, honest, loyal, hard-working, all-American, God-fearing and law-obeying guy fighting crime with science-based super powers under a secret identity (the few superheroines were their relatives). Their main differences were name, powers, costume color and hair color. The Elongated Man comes exactly from this mold.
Despite coming from it, the Elongated Man was the first to break the mold by getting married and giving away his secret identity. The Metal Men, the Doom Patrol, Zatanna, Metamorpho and Deadman were some of the earliest examples of characters created outside the stereotype and the first to follow tendencies established by Marvel Comics: tragedy, diversity, constant conflict, unique personality, etc.
During most of this era, every issue had a self contained, stand-alone story (althought, there were occasional two-parters as well) and the status quo of the characters was kept intact. Towards the end, DC started doing some story arcs (Zatanna's Search, The Outsider) and there were some tragedies (like the deaths of Alfred and the Doom Patrol or the betrayal of Snapper Carr). These were also trends that Marvel Comics started. 

1956

October:

• The Flash, Turtle Man, Iris West (Showcase #4).

November: Lew Moxon, the reasons for the Wayne murder are changed from the Golden Age version, Chill is a hitman instead of a burglar (Detective Comics #235).

1957

February:

• Challengers of the Unknown (Showcase #6).

June: Captain Cold (Showcase #8).

September: Professor Milo (Detective Comics #247).

1958

February: False-Face (Batman #113).

April:

• Legion of Super-Heroes (Adventure Comics #247), 
• Mr. Element (Showcase #13).

July:

• Brainiac (Action Comics #242),
• Space Ranger (Showcase #15).

September: Calendar Man (Detective Comics #259).
October: Bizarro (Superboy #8).

December:

• Adam Strange (Showcase #17).

1959

February: Mr. Freeze (Batman #121), Titano (Superman #127).
March: Mirror Master (Flash #105).
April:

• Grodd (Flash #106),
• the Easy Company (Our Army ad War #81).

May: Pat Boone (Superman's Girlfriend Lois Lane 9).

May:

• Supergirl, Metallo (Action Comics #252),
• the Pied Piper (Flash #106),

• Bat-Mite (Detective Comics #267), 

• Rip Hunter (Showcase #20). 

June: Sgt. Rock (Our Army ad War #83).
August: Suicide Squad, Rick Flag (The Brave and the Bold #25).



October: Green Lantern, Carol Ferris (Showcase #22).

1960 

February:

• Aqualad (Adventure Comics  #269),
• Kid Flash, Weather Wizard (Flash #110).



March:

• JLA, Starro, Snapper Karr (The Brave and the Bold #28),
• Star Hawkins (Strange Adventures #114),
• Captain Atom (Space Adventures #33, Charlton Comics).



May: Elongated Man, he becomes the best buddy of Flash (Flash #112).
June:

• The Trickster (Flash #113),
• Atomic Knights (Strange Adventures #117), 
• Professor Ivo, Amazo (The Brave and the Bold #30).

July: The Puppeteer (Green Lantern #1).
August:

• The Sea Devils (Showcase #27), 
• The Clock King (World's Finest Comics #111).

September:

• Kryptonite man (Superboy #83),
• Cave Carson  (The Brave and the Bold #31).

October:

• Despero (Justice League of America #1),
• Thomas Kalmaku, Weaponers of Qward (Green Lantern #2).

November: Arrowette (World's Finest Comics #113).
December: Captain Boomerang (Flash #117).

1961

January: Faceless Hunters (Space Adventures #124).

February:

• Hawkman & Hawkgirl, Byth (The Brave and the Bold #34),
• Kanjar Ro (Justice League of America #3).



March: 

• Sue Dibny, and Ralph marries her off-panel (Flash #119),
• Hector Hammond (Green Lantern #5),
• the Star Rovers (Mystery in space #66).

April:

• Matter Master (The Brave and the Bold #35),
• Batgirl I (Batman #139).

May:

• Green Arrow joins the JLA (Justice League of America #4),
• Tomar-Re (Green Lantern #6), Haunted Tank (G.I. Combat #87).

April: General Zod (Adventure Comics #283).
June:

• Dr. Destiny (Justice League of America #5), 
• Shadow Thief (The Brave and the Bold #36).

July: Sinestro (Green Lantern #7).
August: The Top (Flash #122).

September:

• Atom, Jean Loring (Showcase #34).
• Flash travels to Earth-2 and meets the Golden Age Flash (Flash #123).

October: Jax-Ur (Adventure Comics #283).
December: Clayface (Detective Comics #298).

1962

January: Qwsp (Aquaman #1).

February:

• G.I. Robot (Star-Spangled War Stories #101),
• Mr. Polka-Dot (Detective Comics #300).

March:

• Metal Men (Showcase #37),
• Felix Faust, Demons Three (Justice League of America #10).

May: Abra Kadabra (Flash #128).
June:

• Floronic Man (Atom #1),
• Dr. Light (Justice League of America #12)..

July:

• Sonar (Green Lantern #14),
• Kru-El (Superman's Pal Jimmy Olsen #62).

August:

• The Elongated Man meets Kid Flash (Flash #130),
• Antonio Rocca (Superman #155).

September: Atom joins the JLA (Justice League of America #14).
October: Carol becomes Star Sapphire (Green Lantern #16).
November: Chronos (Atom #3).

1963

January: Catman (Detective Comics #311).

March: James Bond, Dr. No, Honey Rider, Three Blind Mice (Showcase #43).
June:

• Doom Patrol: Robotman, Negative Man, Elasti-Girl, Beast Boy and Chief, General Immortus (My Greatest Adventure #80),
• Simon Hurt (Batman #156),
• Dr. Polaris (Green Lantern #21).

August:

• Crisis on Earths-One: The JLA meets the JSA , debut of Black Canary on Earth-1(Justice League of America #21), 
• Dexter Myles (Flash #138).

September: 

• Professor Zoom, the Reverse-Flash (Flash #139), 
• Tattooed Man (Green Lantern #23).

October:

• Mera (Aquaman #11), 
• Shark (Green Lantern #24).

November:

• Heat Wave (Flash #140),
• I.Q. (Mystery in Space #87).

December: Eivol Ekdal (Detective Comics #346).

1964

January: The Terrible Trio (Detective Comics #323).

March: Professor T.O. Morrow (Flash #143).

May:

• The Elongated Man gets his feature (Detective Comics #327),
• Chac (Hawkman #1).

June:

• Teen Titans, Wonder Girl (The Brave and the Bold #54), Composite Superman (World's Finest Comics #142).
• Alfred dies, Dick Grayson's aunt Harriet Cooper debuts and replaces him (Detective Comics #328).

July: President John F. Kennedy (Superman  #170).
August: The Crime Syndicate (Justice League of America #29).
September: The Elongated Man meets Batman and Robin (Detective Comics #331).

October:

• Zatanna (Hawkman #4, Zatanna's Search, pt. 1: "The Girl Who Split in Two"), probably the first crossover.
• Sue does the first 'birthday mystery' for Ralph (Detective Comics #332).

November:

• Mento (Doom Patrol #91),
• Hawkman joins JLA (Justice League of America #31).

December:

• Aquaman marries Mera (Aquaman #18).
• The Outsider (Detective Comics #334),
• Martin Beene (Detective Comics #334).

1965

January:

• Metamorpho, Simon Stagg, Java, Sapphire Stagg (The Brave and the Bold #57),
• Billy Warner, Elongated Man's #1 fan (Detective Comics #335).

February:

• Enemy Ace (Our Army at War # 151),
• Zatanna meets Batman (Detective Comics #336, Zatanna's Search, pt. 3: "Batman's Bewitched Nightmare").

March: Getaway Genius (Batman #170).
May: The Riddler of Earth-1 (Batman #171).

June:

• Immortal Man (Strange Adventures #177), 
• Evil Star of Earth-1 (Green Lantern #37),
• Amos Hurd, the Millionaire Cowboy, and wife (Detective Comics #340),
• Zatanna meets the Atom (Atom #19, Zatanna's Search, pt. 2: "World of the Magic Atom").

July: Goldface (Green Lantern #38).
August: Johnny Thunder of Earth-1 (Justice League of America #37).
September:

• Animal Man (Strange Adventures #180),
• the Phantom General (Detective Comics #343).

October:

• Aquababy (Aquaman #23),
• Krona (Green Lantern #40),
• Egg Fu (Wonder Woman #157),
• Johnny Witts (Detective Comics #344).
• Lana Lang becomes the Insect Queen (Superboy #124).

November:

• Judomaster (Special War Series #4, Charlton Comics),
• Blockbuster (Detective Comics #345).

December: The Key of Earth-1 (Justice League of America #41).

1966

January:

• Major Disaster (Green Lantern #43),
• Dial H For Hero (House of Mystery #156),
• Stanley and his Monster (The Fox and the Crow #95),
• Zatanna meets Green Lantern (Green Lantern #42, Zatanna's Search, pt. 4: "The Other Side of the World").

April:

• Enchantress (Strange Adventures #187),
• The Elongated Man meets Green Lantern, the Elongated Man's red uniform, the Monarch of Menace (Detective Comics #350).

May: Cluemaster (Detective Comics #351).

June: Inferior Five (Showcase #62, they reside on Earth-12), Poison Ivy (Batman #181).

July: Dial H calls Plastic Man (House of Mystery #160, first time in a DC publication).
August:

• Chief Miles O'Hara (of the 60s Batman show fame) is introduced to Earth-1 (World's Finest Comics #159) 
• Peter Cannon, Thunderbolt (Peter Cannon... Thunderbolt #1, Charlton Comics),
• Parasite (Action Comics #340),
• Bug-Eyed Bandit (Atom #26),
• Dr. Tzin Tzin (Detective Comics #354).

September:

• Ocean Master (Aquaman #29),
• Nightshade (Captain Atom #82, Charlton Comics),
• The Elongated Man meets Zatanna (Detective Comics #355, Zatanna's Search, pt. 5: "The Tantalizing Troubles of the Tripod Thieves"). 

October:

• It is revealed that Alfred is alive and that he's actually the Outsider, he resumes his dutties as the butler of the Wayne Manor (Detective Comics #356).
• Amalak (Superman #190).

November:

• Blue Beetle II (Captain Atom #83, Charlton Comics),
• Peacemaker (Fightin' 5 #40, Charlton Comics),
• Ultra, the Multi-Alien (Mystery in Space #103),
• Barry marries Iris West (Flash #165).

December: Son of the Plastic Man (Plastic Man, vol. 2 #1, the character resides on Earth-12).

1967

January: Batgirl (Detective Comics #359), B'wana Beast (Showcase #66), Allen Funt (Action Comics #345).

February: , Zatanna's Search ends: The Elongated Man teams up with the JLA (Batman, Hawkman, Atom and Green Lantern) to help Zatanna finally find Zatara (Justice League of America #51, "Z - as in Zatanna - and Zero Hour"), Scarecrow of Earth-1 (Batman #189).
May: The Maniaks (they are a rock band like Josie and the Pussycats, Showcase #68).

July: Lion-Mane (Hawkman #20).
August: Enigma of the Elongated Evildoer! (Detective Comics #367).

September: Black Manta (Aquaman #35).

October: Deadman (Strange Adventures #205), The Elongated Man teams up with the Atom (Detective Comics #368).
November: Woody Allen (Showcase #71), the Awesome Threesome (Aquaman #36).

Notes: I used cover dates for this list (wich means you have to substract a couple of months).

Font types are modified according to the character.

• Important character,
• Character with an equivalent on Earth-2,
• Character with an Earth-2 double,
• Might have Earth-2 double, but their debut date makes it abiguous,
• Crossed-over descendant of an Earth-2 character,
• Created in other media first.
• Not tied to the DCU yet,
• Related to the Elongated Man.  

Continue to:

• The Elongated Man and the Silver Age Timeline!, Part III: Post-Classic (1969 - 1973).  
• The Elongated Man and the Bronze Age Timeline! (1973 - 1985).

Go back to:

• The Elongated Man and the Silver Age Timeline!, Part I: Pre-Classic (1947 - 1956).

Related articles:

• Survivors of the Golden Age! - This article will help you identify character counterparts between Earth-One and Earth-Two.