Mourners of Zion is a term used to refer to a number of Jewish groups through the ages.

1. The Karaite subsect founded by Daniel al-Kumisi
   Daniel al-Kumisi
   Daniel al-Kumisi was one of the most prominent early scholars of Karaite Judaism. He flourished at the end of the ninth or at the beginning of the tenth century...
   
    in the late ninth century CE.
2. A later Karaite community living in Constantinople
   Constantinople
   Constantinople was the capital of the Roman, Eastern Roman, Byzantine, Latin, and Ottoman Empires. Throughout most of the Middle Ages, Constantinople was Europe's largest and wealthiest city.-Names:...
   
    in the late Middle Ages
   Middle Ages
   The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...
   
   . They may have been exiles who left Jerusalem during the Crusades
   Crusades
   The Crusades were a series of religious wars, blessed by the Pope and the Catholic Church with the main goal of restoring Christian access to the holy places in and near Jerusalem...
   
   .
3. A Jewish group living in the mountains of Yemen
   Yemen
   The Republic of Yemen , commonly known as Yemen , is a country located in the Middle East, occupying the southwestern to southern end of the Arabian Peninsula. It is bordered by Saudi Arabia to the north, the Red Sea to the west, and Oman to the east....
   
   , as described by Benjamin of Tudela
   Benjamin of Tudela
   Benjamin of Tudela was a medieval Jewish traveler who visited Europe, Asia, and Africa in the 12th century. His vivid descriptions of western Asia preceded those of Marco Polo by a hundred years...
   
   . They fasted during the week and lived in caves.

Additionally, this term is vital in a phrase used in the Jewish mourning ritual. In mainstream Judaism, mourners
are offered the condolence "המקום ינחם אתכם בתוך שאר אבלי ציון וירושלים", "May The Omnipresent (One)

Names of God in Judaism

In Judaism, the name of God is more than a distinguishing title; it represents the Jewish conception of the divine nature, and of the relationship of God to the Jewish people and to the world. To demonstrate the sacredness of the names of God, and as a means of showing respect and reverence for...

 comfort you among the remnant mourners of Zion and Jerusalem"
throughout the period of Shiva

Shiv'ah

Shiva is the week-long mourning period in Judaism for first-degree relatives: father, mother, son, daughter, brother, sister, and spouse. The ritual is referred to as "sitting shiva." Immediately after burial, first-degree relatives assume the halakhic status of "avel"...

.