ont ory ▁beside ▁the ▁river , ▁the ▁modern - day ▁location ▁of ▁the ▁Royal ▁Palace . ▁Its ▁purpose ▁was ▁to ▁watch ▁the ▁passes ▁of ▁the ▁Sierra ▁de ▁Gu ad ar rama ▁and ▁to ▁initi ate ▁ra ids ▁against ▁the ▁northern ▁Christian ▁countries . ▁The ▁remaining ▁ru ins ▁of ▁the ▁for tr ess ' s ▁wall ▁are ▁still ▁preserved . ▁A ▁small ▁sub urb ▁called ▁M ager it ▁developed ▁to ▁the ▁east ▁of ▁the ▁for tr ess . ▁With ▁the ▁exception ▁of ▁the ▁wall , ▁few ▁structures ▁from ▁this ▁period ▁remain . ▁ ▁The ▁city ▁passed ▁into ▁Christian ▁hands ▁in ▁ 1 0 8 5 , ▁prosper ing ▁into ▁a ▁villa ▁by ▁ 1 1 2 3 . ▁Philip ▁II ▁chose ▁to ▁place ▁his ▁court ▁in ▁Madrid ▁in ▁ 1 5 6 1 , ▁ens uring ▁the ▁swift ▁evolution ▁of ▁the ▁city . ▁Many ▁of ▁the ▁older ▁buildings ▁and ▁monuments ▁of ▁the ▁region ▁known ▁as ▁El ▁Madrid ▁de ▁los ▁Aust rias ▁are ▁from ▁this ▁period . ▁ ▁The ▁city ▁quickly ▁sur pass ed ▁the ▁borders ▁of ▁the ▁current ▁Centro ▁district ; ▁however , ▁the ▁majority ▁of ▁new ▁monuments ▁continue ▁to ▁be ▁built ▁in ▁the ▁area , ▁including ▁the ▁Royal ▁Palace ▁and ▁the ▁Pla za ▁de ▁C ib eles . ▁The ▁Bour bon ▁k ings , ▁especially ▁Carlos ▁III , ▁fix ated ▁on ▁converting ▁Madrid ▁into ▁a ▁city ▁at ▁the ▁height ▁of ▁the ▁new ▁European ▁vill as , ▁using ▁Paris ▁as ▁a ▁model . ▁This ▁resulted ▁in ▁huge ▁invest ments ▁in ▁the ▁infrastr ucture ▁of