According to the legend, Chet received estates near Kostroma in 1330 during the reign of Ivan I of Moscow and was baptized as Zachary.

He also had a vision of the Virgin Mary with prestanding Philip the Apostle and hieromartyr Hypatius of Gangra, which resulted in his healing from sickness.

According to the Russian historian Stepan Veselovsky [ru], the legend appeared only at the end of the 16th century and has serious chronological issues.

The first representative of the family who served Moscow was a grandchild of Zachary called Dmitriy Aleksandrovich Zerno.

He believes that Zachary Chet was an ancient boyar clan that served Daniel of Galicia and appeared in Kostroma at the end of the 13th century.