ay ra , ▁for ▁the ▁l ago on , ▁in ▁reference ▁to ▁the ▁l ago on ▁that ▁formed ▁in ▁the ▁low lands . ▁The ▁Mo ors ▁constructed ▁strong ▁def ensive ▁structures , ▁making ▁the ▁area ▁almost ▁im pre gn able , ▁allowing ▁this ▁area ▁to ▁remain ▁in ▁the ▁hands ▁of ▁their ▁forces ▁longer ▁than ▁other ▁poss essions ▁in ▁Portugal . ▁The ▁development ▁of ▁agricult ure ▁during ▁this ▁period ▁was ▁notable , ▁with ▁the ▁introduction ▁of ▁new ▁techniques ▁and ▁plant ▁species . ▁The ▁Mo ors ▁used ▁the ▁p low ▁and ▁fert il izers , ▁as ▁well ▁as ▁win ches ▁for ▁lif ting ▁the ▁water ▁from ▁the ▁well s , ▁introdu cing ▁the ▁ir rig ation ▁of ▁fields , ▁construct ing ▁d ams ▁and ▁transform ing ▁un c ult iv ated ▁areas ▁into ▁gard ens ▁and ▁orch ards . ▁ ▁Middle ▁A ges ▁The ▁Christian ▁con quest ▁of ▁the ▁region ▁began ▁at ▁the ▁end ▁of ▁the ▁ 1 2 th ▁century . ▁When ▁Af onso ▁III ▁of ▁Portugal ▁occupied ▁the ▁throne , ▁most ▁of ▁the ▁Al gar ve ▁had ▁already ▁fallen ▁into ▁the ▁hands ▁of ▁the ▁Christians . ▁Tem pl ar ▁and ▁Hospital er ▁Kn ights , ▁military ▁and ▁religious ▁orders ▁that ▁supported ▁the ▁Re con qu ista , ▁assault ed ▁many ▁of ▁the ▁lands ▁occupied ▁by ▁the ▁Arab s , ▁but ▁were ▁never ▁successful ▁in ▁taking ▁Al buf e ira . ▁It ▁was ▁following ▁the ▁capture ▁of ▁Far o ▁that ▁the ▁sie ge ▁of ▁Al buf e ira ▁became ▁un support able . ▁En