Hilarius Altobelli also made a critique of the then known house systems in his 'Tabulae Regiae divisorum duodecim partium coeli ad mentem Ptolemaei' (1628). Knappich: 'After Magini another Italian astrologer P. The Italian monk and mathmatician Placidus de Titis (1603-1668) is erroneously considered to be the 'Founding Father' of this system.
The essential idea is that the conditions laid out by Ptolemy for the Primary Directions are also used to formulate and calculate the so-called Placidus House System. The mathematical foundations for the house system that is most popular today, were first calculated and formulated by the astronomer, mathematician and cartographer Giovanni Magini. Chart according to Ptolemaic method Magini
