Historical reference: Do not rely on this information. It is very old. About this collection
Regiomontanus, otherwise Johann Muller, a noted astronomer, born in 1436 at Kbnigsberg. He studied at Leipsic, and, after assisting Purbach in Vienna, went to Italy, whence he returned to Vienna and accepted a professorship. He built an observatory and founded a printing office at Nuremberg, became Archbishop of Ratisbon and died in 1476. Besides writing some astronomical works, he reformed the calendar at the request of Pope Sixtus IV.