You can see from our picture why this coin is called a 'long cross penny' -- because it has a long cross. There were also 'short cross pennies' as shown in one of our supplemental pictures below. These coins were minted in silver during the medieval period and usually carry a face-on portrait of the reigning monarch. They often carry the inscription POSVI DEVM ADIVTOREM MEVM (I have made God my helper).
Before the officials wised up and started minting long cross coins, the pattern on the reverse was of the short cross variety. Unscrupulous people would shave the edges off the silver coins, collect the precious metal, and melt it down for bullion. With the short cross, no one was really sure just how big the coin should be. The long cross design shows immediately shortened diameter coins, and the thievery stopped.
The coin in our main picture (upper right) comes from Spink in London, where it sold for 340 British pounds (about $580 US dollars) in a 2011 auction. It is in beautiful condition, with little wear and great eye appeal. This sends the price upward.
Since the pattern and inscriptions are the same for all denominations, the size and weight determine face value. Here are some typical weights:
PENNY (one pence): 0.9 grams, plus/minus 0.5 grams
HALF GROAT (two pence): 1.8 grams, plus/minus 0.8 grams
GROAT (four pence): 3.6 grams, plus/minus 1.0 grams
These coins were minted during the reigns of several monarchs, from Edward I (1272AD) to Richard III (1485AD), including, in order, Edward II, Edward III, Richard II, Henry IV, Henry V, Henry VI, Edward IV, and Edward V.
Placing accurate values on these coins is difficult. By far the most important factor is legibility and eye appeal. Date means little, although there are some subtle pattern differences that can be very valuable if sold to the right collector. If you have a nice looking coin, be sure to bring it to a knowledgeable collector of professional coin dealer for an in-person look. Very, very approximately:
PENNY AND HALF GROAT:
worn: $35 US dollars approximate catalog value
average circulated: $180
well preserved: $400
average circulated: $6500
well preserved: $12000
groats of Edward III from the his fourth coinage, pre-treaty period are common and catalog at $120 when worn, $1200 well preserved
Our second picture comes from Tony Clayton's Pictures of Coins of the UK web site, and it is perhaps the best web site on the web for this topic. CoinQuest thanks Tony Clayton for use of his coin photo. On Tony's site, you will find dozens of different varieties of long cross coinage.
Another favorite site is Time Line Originals with plenty more long cross coins to look at.
There are also specialized collectors of such material on ForumAncientCoins and, of course, CoinTalk, where the real coin experts live.