in Scots law there were various types, those in the name of the Crown being under the signet seal; most of the types are covered under the headings, caption, cocket, diligence, fire and sword, horning, inhibition, lawburrows, marque, poinding, regress, reprisal, respite and slains. "Letters of four forms" were a form of diligence incorporating successive means of getting debtors to pay up. They rapidly became obsolete; like apprising they may have been considered too abrupt for the popular taste (given that they seem to have been the horning, poinding and caption in one)