Playing cards arrived in Europe in the fourteenth century, most likely carried by traders from the Islamic world. The Mamluk deck they brought with them grouped cards into four suits: cups, coins, swords, and polo sticks. These were practical categories, drawn from the world of the court and the military, nothing more symbolic than that. The suits changed again when the deck reached German-speaking Europe in the fifteenth century, turning into hearts, bells, leaves, and acorns, images pulled from rural and hunting life. And something else happened alongside the redesign. These new suits started to loosely map onto the four estates of medieval society: the clergy, the nobility, the merchants, and the peasantry. A deck of playing cards had quietly become a small, portable model of the social order, one you could carry in your pocket and deal out at a table. The French simplified those shapes into the ones still in use today, largely to make printing faster and cheaper. For a while, though, the social meaning travelled with the new shapes. Hearts stood for the church. Diamonds, sharp-edged and valuable, stood for merchants and trade. Spades, named after the word for a pike or sword, stood for the military nobility. Clubs, originally a trefoil, stood for the peasantry and the working land. Four suits, four ways of belonging to society: those who prayed, those who fought, those who traded, and those who worked. Where the Meaning Ran OutBy the time the deck reached England, almost none of that survived. The suits became conventional. Nobody dealing a hand of whist was thinking about clergy or peasants. The shapes had become just shapes, stripped of the meaning they had briefly carried across the Channel. But in other traditions, particularly in tarot and the esoteric currents of the sixteenth to nineteenth centuries, the suits continued to be read as the four elements, the four temperaments, the four fundamental patterns of human character. This wasn’t a continuation of the estates mapping so much as a separate set of people, in different places and centuries, reaching for the same convenient number for their own reasons. Four kept turning out to be a workable way to sort human variety into categories small enough to remember and large enough to say something real. Somewhere in that six-hundred-year drift, the suits stopped meaning anything at all. Which raises an obvious question. StrongSuits, the card-based team development tool I work with, also organises itself around four suits. Is that a continuation of any of this? Not really. It’s a separate, more recent piece of work, built from research done mostly in the twentieth century, that happens to land on the same number. Both are worth telling on their own terms, so here is where StrongSuits actually comes from. A Different Deck, Built for a Different ReasonWhen Dave Corbet designed the four suits used in StrongSuits, he wasn’t reaching into medieval symbolism. He was drawing on research from organisational psychology, most of it decades old and well tested. The most direct influence is the work of William Moulton Marston, whose 1928 book Emotions of Normal People proposed four behavioural patterns based on two distinctions: whether a person tends toward active or passive engagement, and whether they perceive their environment as broadly favourable or unfavourable. From these two axes, Marston derived four patterns: Dominance, Inducement, Submission, and Compliance. This became the theoretical foundation for what we now know as the DISC model, one of the most widely used behavioural frameworks in organisational life. Linda Berens developed Marston’s thinking further, focusing specifically on how people interact with others rather than on underlying personality traits. She identified four interaction styles. Some people prefer to have a plan and know what is going to happen before they act. Others want to focus on results and simply get things done. Others again prefer to get along, taking time to integrate different perspectives before moving forward. And others lead with inspiration, wanting to energise and persuade those around them. These four interaction styles map directly onto the four suits in StrongSuits: Spades for drive and getting things done, Clubs for relationship-building and integration, Hearts for passion and inspiration, Diamonds for precision and upholding standards. The suits are not arbitrary. Each one represents a coherent cluster of strengths that belongs to a recognisable way of showing up in the world. Understanding these differences matters because of what happens when people do not feel safe to show them. When Google launched its internal Project Aristotle research in 2012, studying more than 180 teams to find out what made the best ones effective, the result was not what anyone expected. Individual talent, team composition, and collective expertise all mattered less than one thing: whether people felt safe to speak up, share mistakes, and bring their real perspectives to the work. This built directly on the research of Harvard Business School professor Amy Edmondson, who had been studying team psychological safety since the late 1990s and whose framework underpinned Google’s findings. For many HR professionals and coaches, this is now familiar ground. What StrongSuits offers is a practical way into it: a structured, low-threat starting point for the kind of honest conversation about strengths and working styles that psychological safety requires but rarely just happens on its own. Strengths as the Unit of CurrencyOnce the four suits were established, the task was to identify the thirteen strengths that belong to each one. This was not a casual process. The development of the StrongSuits deck drew on a wide range of workplace competency frameworks: the University of California core competency model, the UK Civil Service competency framework, Harvard University’s competency dictionary, and research published in the Harvard Business Review by Zenger and Folkman, among others. A long list of over a hundred positive workplace qualities was assembled and then refined, with thirteen strengths selected for each suit. | 
