A: San Lorenzo de El Escorial, Comunidad de Madrid, Spain
The so-called Arabic numerals were invented in India and tranferred to the Arabs who developed the system in in the moorish empire of Al-Andalus in the Iberian peninsula. The oldest record of the use of Arabic numerals in Europe is a leaf in the codex Virgilianus, ms. lat. DI.2f.9v preserved in Madrid at the Biblioteca S. Lorenzo del Escorial.
Frugon, Inventions of the Middle Ages (2007) 52, figure 36, & footnote 95.