Back in the day, baseball’s home plate was often a perfectly round – and, later, a perfectly square –  chunk of marble. Iron or wood would do in a pinch. Or, a hunk of anything, really, tough enough to withstand baseball’s roughhousing 19th-century games.

The Dodgers’ broadcaster Vin Scully explained the history of home plate during a game last season. Listen here.

Home plate is, technically, called “home base” but rarely is it called that, in the same way that the Cincinnati Reds are rarely called the “Red Stockings” even though that is their name. Technically.

Should you wish to build your own 21st-century home plate, you will forgo the marble (and the round and the square). Instead, find yourself a nice piece of white rubber and carefully carve it into a 20-pound pentagon.

Emphasis on “carefully.” Because home plate’s dimensions and placement are very, very precise.

(Explicitly precise dimensions in the infield surrounded by decidedly imprecise outfields is what makes baseball a perfect game.)

The pentagon shape was settled on in 1900 to help umpires better see the strike zone.

(You may insert your favorite umpire joke here. Or, try this one … Why are umpires so fat? They always clean their plates!)

Thank the 1880s Baltimore Orioles for the creation of a home plate made of rubber.

(Thank you for home plate, Orioles. Oh, and while I have you, where’s that ace starting pitcher you’ve been promising us?)

(Purist Alert: These 19th-century Orioles do lead to the rubber home plate, but they didn’t really evolve into today’s Orioles. They also did not evolve into the New York Yankees – a later, traitorous 1901 Orioles’ incarnation did that.)

The rubber home plate was the invention of lefty pitcher Robert Keating, who pitched one big-league game for the Orioles in 1887.

Keating’s one-game career was rough – a complete-game loss that left him with a career 11.00 ERA.

Apparently, Keating knew his baseball days were numbered, and that same year he patented one of many dozens of inventions that he would create during his lifetime – a much safer rubber home plate to replace the stone and iron ones that often led to injuries.

Keating is rarely remembered for this important contribution to baseball.

Instead, he is best known for the Keating Bicycle, a “safety bicycle” which had front and rear wheels that were the same size. This was an alternative to the dangerous big front-wheel numbers that people seemed all crazy for in the 1880s.

(Keating, apparently, was a “safety first” man – a safer home plate, a safer bicycle, and he also invented an early version of the “safety razor.”)

Keating fans will also tell you he invented the first motorcycle in 1901, a full year before it was “officially” invented by someone else.

But, back to baseball. Here’s what you should know about home plate.

* It may have informally been called “home” before then, but it was the famed Knickerbocker Rules of 1845 that formally named the base where a batter swings and a runner scores as “home.”

* Major League Baseball’s rules “suggest” that home plate be positioned in an “East-Northeast” direction.

This is to accommodate batters during sunny day games. Of course, most of today’s baseball is played at night under lights – or indoors – so it’s much less important. Still, rules are rules, even when they’re just suggestions, and you’ll see that many modern ballparks still properly place home plate to the east-northeast.

* Modern-day rubber home plates are durable, sure, but they’re no marble. Today’s major league teams will usually wear through two home plates each season (they’ll bring in a fresh plate around the All-Star Break).

Minor league teams will often squeeze a couple seasons out of their home plates.

(Bulldog Field Equipment, based here in Virginia, supplies home plates and pitching rubbers to many major- and minor-league teams. Their “double-sided” plates weigh 40 pounds and can be flipped over to increase their lifespan.)

* Umpires have their own very specific rules for the care of home plate. They will dust it with a brush before each half inning and whenever needed. The umpire will step to the front of the plate, turning his back to the pitcher’s mound before dusting, so as not to moon the fans when he bends over. Players don’t dust off the plate. Ever.

* Whether rubber or marble, it’s not easy to steal home, which makes it one of baseball’s rarest and most exciting plays. Detroit’s Ty Cobb stole home 54 times in his career – the most of any ballplayer.

On those few occasions when a runner on third attempts to steal home, this is what almost always happens:

But, once in awhile, this happens:

Jackie Robinson stole home 19 times in his career, but, to this day, catcher Yogi Berra insists that Robinson was out during this famous play during the 1955 World Series.

Berra told Sports Illustrated in 2009, “The ump never saw the play good. … He was short and never got out of his crouch. The hitter even admitted later that Jackie was out. And he had a great view.”

Asked what he remembered most about one of baseball’s most famous plays, Yogi says, “Mostly, I remember he was out.”

(Special Thanks to Jason Grohoske & Steve Ruckman of the Double A Richmond Flying Squirrels who answered my questions about the life span of modern day home plates. Go Squirrels!)

(Much of the information on Robert Keating is from the fine research of Daniel E. Ginsburg of the Society of American Baseball Research. Find more here.)

More of my posts on the evolution of “home”:

Skizzle, Sweet Skizzle

Don’t Try This At Home