During centuries Registan Square was the center of Samarkand. The word  Registan means "sand place". There was a river running there many ages  ago, before building the first Madrassah on the square. Years passed,  the river dried out and left lots of sank there, that was the first  place where the first Madrassah was built in the beginning of the 15th  century and named Registan square. As the Madrassah was first built, all  the holidays, parades, festivals and Sunday bazaars took place. 
The ensemble consists of three Madrassah: Ulugbek Madrassah (15th century), Sher - Dor Madrassah (17th century) and Tilla-Kari Madrassah (gold covered)(17th century).
