I have been researching the Cowan family of Clonkeen/Glenkeen townland for
some years and just the other day found some more information about how land
ownership in Ireland worked in the 1800s.
There is a memorial of the Archdale-Cowan deed from 1749 on familysearch :
The original Cowan lease was a lease for lives renewable forever. A lease
of lives means that the person taking the lease, the leasee, nominated three
people in the lease and the lease expired when all three people named had
died. Often the leasee would nominate young family members and sometimes
their ages were recorded. In a lease for lives renewable or a perpetual
lease a new name could be inserted when one of the lives died on payment of
a renewal fine.
In 1849 the Renewable Leasehold Conversion Act was passed. Lessees holding
leases for lives created before the 1st of August 1849 were only given the
right to obtain a grant and frequently the right to convert the lease into a
fee farm grant was not exercised and with the passage of time, lives were
not renewed. It is not known if the Cowan lease for lives renewable forever
was converted to a fee farm grant after 1849, although family correspondence
in 1868 mentions a "potential act of parliament which may have changed the
terms of the Clonkeen lease".
In the memorial of the 1749 deed, it appears to mention that there was a
yearly rent payable by the Cowans: 'for and during the natural life and
lives of such other person or persons as by virtue of a covenant for renewal
in said deed shall from time to time for ever be added at and under the
yearly rents in said deed renewed and in said deed there is a covenant of
Renewal for ever and other usual clauses'.
And if you are interested in researching any legal terms from the 18th
century, try the 'New Law Dictionary' from 1739