The manner or qualification gives law to the gift, and the manner is to be observed against common right and against law, because manner and agreement covenants inserted in a conveyance or lease, overrule law. As if it be said, "I give to and the agreements, whether in writing or by parol, entered into between parties, have, when duly executed and perfected, and subject to certain restrictions, the force of law over those who are parties to such instruments or agreements. Broom's Max. 303, [538.] Story on Partn. § 134. This maxim applies to all contracts not offensive to sound morals, or [contrary] to positive prohibitions by the legislature. Story on Bailm. § 32. Modus legem dat donationi. Manner gives law to a gift. Bract. fol. 17 b. Fleta, lib. 3, c. 9, § 1. Co. Litt. 19 a. Wright on Ten. 21. Broom's Max. [347.] The manner in which an estate is declared to be given by a feoffment (or gift) governs its operation, and the course of the estate under it. If given to a man and his heirs, a fee is passed by the force of these words. But if given to a man, without limiting or expressing any estate, [or, as it may be said, without declaring any modus,] the grantee has barely an estate for life.* 2 Bl. Com. 310. Both the above maxims are constantly quoted in modern law, especially the first, which may be considered as the fundamental principle of the law relating to contracts. Broom's Max. 303. Originally, they were rules of the old English law of real estate, and, according to Blackstone, the latter was derived from the feudal maxim, Tenor est qui legem dat feodo. 2 Bl. Com. 310. It is interesting to trace them both to the following passage of Bracton, which is quoted to complete the illustrations already given: MODUS enim LEGEM DAT DONATIONI, et modus tenendus est contra jus commune, et contra legem, quia MODUS ET CONVENTIO VINCUNT LEGEM; ut si dicatur, do tali tantam terram cum pertinentiis in N. habendam et tenendam sibi et hæredibus suis quos de carne sua, et uxore sibi desponsata, procreatos habuerit. Vel sic: Do tali et tali uxori suæ, vel cum tali filia mea, &c. Habendum et tenendum sibi et hæredibus suis de carne talis uxoris, vel filiæ exeuntibus, such a one so much land, with the appurtenances, in N. to have and to hold to him and his heirs whom he shall have begotten of his own body and his wife that is espoused to him." Or thus, "I give to such a one, and such a one his wife, or with such a one my daughter, &c. to have and to hold to him and his heirs of the body of such wife or daughter issuing, or begotten, or to be begotten." In which case, since certain heirs are expressed in the donation, it will be seen that the descent [of the land] takes place only to the said heirs in com mon, by the modus or qualification annexed in the donation, all the other heirs being wholly excluded from the succession, because the donor willed this. Bract. fol. 17 b.