## Facts

- The Crown issued letters patent granting an exclusive right to import, make, and sell playing cards in England for a term of years.
- The monopoly interest was ultimately vested in Edward Darcy, who agreed to pay an annual sum to the Crown and to use a marking seal for cards.
- Thomas Allin, a London haberdasher, made and sold playing cards without Darcy’s license.
- Darcy sued in an action on the case, alleging the unlicensed competition infringed the patent and caused economic loss.
- The dispute required the court to determine whether the Crown-granted exclusive trading right was legally valid and enforceable.

## Issues

1. Whether the Crown could grant, by prerogative, an exclusive right over a common trade that barred others from making and selling ordinary goods.
2. Whether a patent conferring the sole making, importation, and sale of playing cards was valid at common law and enforceable against a non-licensee.

## Decision

- Judgment was for Allin.
- The court held the monopoly patent void at common law.
- Because the patent was invalid, Darcy could recover nothing in his action.

## Legal Principles

- A general monopoly over an existing, ordinary trade is void at common law.
- Such monopolies are unlawful restraints on the liberty of subjects to work and trade, and are contrary to the welfare of the realm.
- Courts identified recurring harms from monopolies: exclusion of skilled workers from their trades, increased prices and reduced quality, and private gain achieved at public expense.
- Royal prerogative does not authorize grants that conflict with common-law limits and the public good; a claimed regulatory purpose cannot validate a broad trade monopoly.
- Exclusive privileges were treated differently where tied to introducing a genuinely new manufacture or industry; a monopoly over an established trade without such justification is unlawful.

## Conclusion

The court refused to enforce a Crown patent granting exclusive control of a common commercial activity, holding that broad trade monopolies are void at common law because they restrain lawful work and competition and harm the public.


Darcy v. Allein (The Case of Monopolies), 77 Eng. Rep. 1260 (K.B. 1602)