The Arab conquests brought about the collapse of the Sassanid Empire and a great territorial loss for the Byzantine Empire. Though spectacular, the Arab successes are not hard to understand in hindsight. The Sassanid Persian and Byzantine empires were militarily exhausted from decades of fighting one another. This prevented them from dealing effectively with the mobile Arab raiders operating from the desert. Moreover, many of the peoples living under the rule of these empires, for example Jews and Christians in Persia and Monophysites in Syria, were disloyal and sometimes even welcomed the Arab invaders, largely because of religious conflict in both empires.
Some of the individual conquests are mentioned here:
The Byzantine-Arab Wars were between the Byzantine Empire and at first the Rashidun and then the Umayyad caliphates.
Under the Rashidun there were the conquests of Syria (637), Armenia (639), Egypt (639) and North Africa (652). Under the Umayyads the continuing conquest of North Africa (665), the second Arab siege of Constantinople (717-718) and the conquest of Tbilisi (736). In 827 there followed the conquest of southern Italy (827).
The last ruler of the Sassanid Empire in Persia was defeated by the Rashidun in 633 and 636, but the final military victory didn't come until 642 when the Persian army was destroyed.
During the seventh century the Umayyad fought successfully against the early Rajput in north India and in Central Asia.
In 711, a Muslim expedition defeated Raja Dahir at what is now Hyderabad in Sindh and established Umayyad rule by 712. The Umayyad brought under control the whole of what is modern Pakistan, from Karachi to Kashmir and reached the borders of Kashmir within three years. But rather soon afterwards semi-independent Arab ruled states developed.
The conquest of the Iberian Peninsula began when the Moors (mostly Berbers with some Arabs) invaded Visigothic Christian Iberia (modern Spain, Portugal, Gibraltar, Andorra) in the year 711. They landed at Gibraltar on April 30 and worked their way northward. This territory, under the Arab name "Al-Andalus", became first an Emirate and then an independent Umayyad Caliphate after the overthrowing of the dynasty in Damascus by the Abbasids. In 1031 the Christian kingdoms started the Reconquest up to 1492, when Granada, the last kingdom of Al-Ándalus fell under the Spanish Kings.
In Sub-Saharan Africa, the Sahelian kingdom expanded Muslim territories far from the coast. Muslim traders spread Islam.
The modern era saw the rise of three powerful Muslim empires: the Ottoman Empire of the Middle East and Europe, the Safavid Empire of Persia and Central Asia, and the Mughal Empire of India; along with their contest and fall to the rise of the colonial powers of Europe.
The Mughal Empire declined in 1707 after the death of Aurangzeb and was officially abolished by the British after the Indian Rebellion of 1857.
Key space
In cryptography, the key space of an algorithm refers to the set of all possible keys that can be used to initialize the cryptographic algorithm. For example, if an algorithm works using a key that is a string of 10 bits, then its key space is the set of all binary strings of length 10 bits; i.e. we have key space of size 2 = 1024.
To avoid attackers from guessing the key using a brute-force attack, the key space is usually designed to be very large. Another needed attribute is that the key space designed to be "flat", having no or very few weak keys.
The block cipher Rijndael/AES uses a key of up to 256 bits, resulting in a key space containing about 2 which is over 1.1579 × 10 keys. This makes it "computationally infeasible" to check each possible key by brute force.
In the DES block cipher, a 56-bit key is used, resulting in a relatively small key space of size 2.
The ROT13 cipher is only designed to prevent people from accidentally reading messages (e.g. movie plot details). As there is no key, the key space is therefore empty.
Roger Williams (theologian)
Roger Williams (December 21, 1603 – April 1, 1683) was an English-American Puritan, and a Calvinist-Baptist theologian. He was widely known as a supporter of religious toleration and separation of church and state. He also supported fair dealings with Native Americans. In 1644, he received a royal charter creating the colony of Rhode Island, named for the main island in Narragansett Bay. He is believed to have started the first or second Baptist church in the United States. He is known to have left the church soon afterwards, saying, "God is too large to be housed under one roof."
These are some famous descendants of Roger Williams:
Unitarianism
Unitarianism is a term that describes some forms of Christianity. Unitarianism can be described as the belief that God is just one person. This is different from what most other Christians think, which is that God is three different people all in the same person. That belief is called Trinitarianism. Unitarian Christians believe in Jesus of Nazareth. They think that Jesus was a great leader and prophet, but they generally do not think that Jesus is part of God himself.
The "Son of God" is a being that existed before Jesus' human life. It is called the Logos who dwelt with God in the beginning and then was born as the man Jesus. However, he is not eternal, but had a beginning of existence. God created him. This theology is commonly called Arianism, but there are many varieties of this form of Unitarianism. They range from the belief that the Son, before he came to earth, was a divine spirit of the same nature as God to the belief that he was an angel or other lesser spirit creature of a wholly different nature from God. Arius' views are only one variation of this theology.
Whatever the case, in this belief system, Jesus is beneath God, but higher than humans (and has always been so). This concept could be referred to as "elevated subordinationism." It is associated with early church figures such as Justin Martyr, Lucian of Antioch, Eusebius of Caesarea, Arius, Eusebius of Nicomedia, Asterius the Sophist, Eunomius, and Ulfilas, as well as Felix, Bishop of Urgel and others who believed that Jesus was God in his divine nature but his divinity in his human nature was through adoption. Arian forms of Unitarianism remain among Unitarians in Transylvania, Hungary, France, and several countries in Africa. Famous Arian Unitarians include Isaac Newton, Andrews Norton and Dr. William Ellery Channing.Ralph Waldo Emerson's father was a Unitarian pastor.
Since the 19th century, several Evangelical or Revivalist movements also used an elevated subordinationist theology. This can be best described as Nontrinitarianism, rather than Unitarianism. Important figures include Barton W. Stone and Charles Taze Russell. Theologies among Evangelical Unitarians are sometimes classed as Arian, and sometimes Sabellian (Jesus is God in the flesh, the manifestation of God, who exists as a single person) and the Chinese-based sabbatarian True Jesus Church. Other modern non-trinitarian churches, such as the Filipino-based Iglesia ni Cristo, may also be included, although they reject the "unitarian" name to avoid confusion. Jehovah's Witnesses also have a nontrinitarian theology with specific traits. The Christian Churches of God (CCG) is another Unitarian Church with a World Conference. It has a lot of material on Unitarian theology and history and holds the doctrine of the Pre-existence of Jesus Christ. CCG like other Sabbatarian Churches of God trace their ancestry back to the early church and follow biblical law. The CCG and Sabbatarians are sometimes erroneously called Arians due to the pejorative Trinitarian use of that term and also that of Subordinationists (see Bibliography).