Definition
A bill single is a written, unconditional promise to pay a specified sum of money to a named payee at a stated time. It is typically executed under seal. The instrument expresses no penalty for non-payment, which distinguishes it from a bill penal. When under seal, it is sometimes referred to as a bill obligatory.
The bill single is a historical debt instrument — a precursor to the modern promissory note — used to evidence a simple, direct obligation between two parties without the conditional or penal features found in related instruments of the same era.
Common Confusion
BILL SINGLE vs. BILL PENAL: These two instruments share the same basic structure — a written, sealed promise to pay — but diverge on consequences. A bill penal specifies a penalty (typically double the principal) as a consequence of non-payment. A bill single carries no such penalty; the obligor is liable only for the stated sum. Researchers encountering either term in historical documents should confirm which instrument is at issue before drawing conclusions about the parties' rights and remedies.
BILL SINGLE vs. PROMISSORY NOTE: In modern practice, the promissory note has entirely displaced the bill single. The two instruments perform the same basic function, but the bill single was commonly under seal (carrying distinct legal consequences at common law, including a longer limitations period and different rules of evidence), whereas promissory notes are not sealed instruments. Do not assume that historical references to a bill single can be read interchangeably with the modern promissory note without accounting for these procedural and evidentiary differences.
Why It Matters in Research
The bill single is an archaic instrument and will appear almost exclusively in pre-twentieth century sources. Researchers should note several navigational points:
Regional usage is not uniform. Rapalje & Lawrence specifically identifies the instrument as having sustained use in certain Southern states and in Pennsylvania. A researcher working with legal records from those jurisdictions — particularly colonial-era and antebellum court records, estate inventories, and debt litigation — is more likely to encounter bills single than a researcher focused on New England or the mid-Atlantic outside Pennsylvania.
The seal matters. At common law, a sealed instrument was treated differently from a simple contract: it was not subject to the same pleading rules, it carried a longer statute of limitations, and consideration was not required to be proved independently. A bill single described as being "under seal" must be analyzed under those rules, not under the rules governing unsealed instruments or modern promissory notes.
Terminology is inconsistent across sources. Historical documents and court records may use "bill single," "bill obligatory," and "single bill" interchangeably, or may use them with subtle distinctions depending on jurisdiction and period. When the presence or absence of a seal, or the presence or absence of a penalty clause, is legally material to the dispute under research, verify the instrument's actual terms rather than relying on the label applied in secondary sources.
Equity court records. Disputes over bills single frequently appear in chancery and equity court records, where obligors sought relief from harsh enforcement of sealed instruments. Researchers tracing debt litigation in historical equity courts should be alert to this instrument as a common underlying document.
Historical Dictionary Support
Black's Law Dictionary defines a bill single as a written promise to pay to a named person or persons a stated sum — the entry as available is truncated but consistent with the instrument's basic character. Rapalje & Lawrence provides the more complete treatment: an unconditional written engagement to pay a named payee a specified sum at a stated time, typically under seal, carrying no penalty clause. Both sources agree on the essential elements and on the distinction from the bill penal.
Neither source situates the bill single within the broader history of negotiable instruments or explains its displacement by the promissory note. Researchers needing that developmental context will need to consult treatise literature on the law merchant and negotiable instruments history — the historical dictionaries treat the term descriptively rather than historically.
Rapalje & Lawrence's note on regional usage (Southern states and Pennsylvania) is the more practically useful observation for archive and corpus research and does not appear in Black's entry.
Jurisdictional Note
The bill single had particular staying power in Pennsylvania and parts of the American South, where it remained in use well into the nineteenth century. In jurisdictions where the instrument was less common, it was effectively superseded earlier by the promissory note. Statutory abolition of the legal effect of seals in many states during the nineteenth century further eroded any practical distinction between the bill single and an unsealed promissory note.