This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
The king's courts had found at least three classes of contract which are usually classed as formal contract, which were known to the Anglo-Saxon law or to the law-merchant, and a fourth class which was the direct result of Norman influence. The formal contracts from Anglo-Saxon law and from the law-merchant were the executory contract in which earnest had been paid, the contracts which had been made binding by a hand-shake, and the contract which was shown by the tally. For some time the courts seem to have hesitated over the question whether a seal was necessary to a formal contract, or whether a written contract, or even an oral contract made in one or more of these other solemn forms would not be sufficient.1 Gradually the types of formal contract other than that under seal were excluded from the jurisdiction of the king's courts.
Some of the local courts appear to have continued to enforce the other types of formal contract. Here again the king's courts would have broadened their jurisdiction greatly if on this point they had adopted the law of these local courts. At the same time, however, this gain in the early law of contract would probably have been paid for later. The king's courts would have developed a number of different types of formal contract which would have undoubtedly interfered with the ultimate development of a broad, simple theory of contract. It was the very delay on the part of the king's courts in recognizing contracts in general that enabled them eventually to adopt a fairly simple and rational theory of contract. By the reign of Edward I, it was settled that a sealed instrument was necessary to prove a covenant. While this is stating substantive law in terms of evidence, it is only doing what is done in our law to this day. The action of covenant then, became restricted to the sealed contract.
3 Biatcton, f. 100; Twiss's edition, Vol. II, p. 117.
4 Bracton, f. 34; Twiss's edition, Vol I, p. 267.
5 Pollock & Maitland, History of English Law (2d Ed.), Vol. II, 216.
1 Pollock & Maitland, History of English Law (2d Ed.), Vol. II, 219, 220.