The current regulation and the idea of the mortgage is inherited from Roman law. Specifically, in ancient Rome there were two main ways to secure a debt, with real effectiveness:
The subsequent refinement resulted sometimes when the debtor needed assets to pay the debt, it was agreed the pledge without transfer of possession to the creditor. It was used this waz for the lessors of the land would to ensure payment to the tenant, ignoring their farming tools (which would in any case need to work, so they could not give to the creditor).
This figure was the germ of the current mortgage. However, for reasons of legal certainty, given that lack of possession remained as hidden charge, it was not until the establishment of the Accountants mortgage, then converted into Property Records, which brought the end of the mortgage as hidden burden through land registration, when it began to be widely used as a great motivator territorial credit.
Image http://en.wikipedia.org/wiki/File:Ontario_farm.jpg
Translated and adapted from Wikipedia under GNU Free Documentation License.