in Feudal Law, was a feudal burden, only incident to the king's tenants in capite, and not not to those who held of inferior or mesne lords. It was a right which the king had, when any of his tenants in capite died seized of a knight's fee, to receive of the heir (provided he were of full age) one whole year's profits of the lands if they were in immediate possession, and half a year's profits if the lands were in reversion expectant on an estate for life. This seems to be little more than an additional relief (see Relief); but grounded upon this feudal reason, That by the ancient law of feuds, immediately upon the death of a vassal the superior was entitled to enter and take seisin or possession of the land, by way of protection against intruders, till the heir appeared to claim it, and receive investiture; and for the time the lord so held it, he was entitled to take the profits; and unless the heir claimed within a year and day, it was by the strict law a forfeiture. This practice, however, seems not to have long obtained in England, if ever, with regard to tenures under inferior lords; but, as to the king's tenures in capite, this prima seisin was expressly declared, under Henry III. and Edward II. to belong to the king by prerogative, in contradiction to other lords. And the king was entitled to enter and receive the whole profits of the land, till livery was sued; which suit being commonly within a year and day next after the death of the tenant, therefore the king used to take at an average the first-fruits, that is to say, one year's profits of the land. And this afterwards gave a handle to the popes, who claimed to be feudal lords of the church, to claim in like manner from every clergyman in England the first year's profits of his benefice, by way of primitive, or first-fruits.

All the charges arising by primer seisin were taken away by 12 Car. II. c. 24.