Sources for Genghis Khan:
http://www.pma.edmonton.ab.ca/vexhibit/genghis/biog.htm
Genghis Khan became the sole leader of the Mongolian Empire simply because of his military genius and skills as a tactician. Unlike many other leaders however, Genghis Khan did not get his position thanks to succession, he had to work for it. In 1189 he was elected ruler of a small tribe named, Kiyat. It was from this position that Genghis Khan began unifying and conquering the empire that he would soon rule. He started by unifying the Khuriltai Steppe. Once the unification of this area had been completed Genghis Khan was named emperor of the land and was also dubbed "emperor of all emperors" and "oceanic ruler". Genghis Khan continued to use his military to gain land to his new empire. Nobody would challenge him or his rule and he soon became one of the finest emperors the world has seen yet. It is stated clearly within the website that Genghis Khan became ruler solely because of his amazing leadership. The source gives an explanation that tells what Genghis Khan had to do, as far as conquering and uniting, to become the leader of the Mongolian Empire. I can make the assumption, based on the source, that Genghis Khan became the leader of Mongolia because he was so intellectual, fierce, and violently powerful.

http://www.nationalgeographic.com/genghis/trail.html
Genghis Khan was born into an average family. At the time his name was Temujin, meaning "blacksmith". When Genghis Khan was only nine years old his father was murdered by the Tartans because he had stole from them. His father was a somewhat respected tribe chieftain but now Genghis Khan and his mother were considered to be outcasts. Genghis Khan became a force within the Mongolian Steppe. Multiple tribes decided to make him their khan or leader. Thanks to his intellect, wits, and charismatic personality Genghis Khan attracted many followers from many different tribes. From the year 1200 to the year 1206 Genghis Khan defeated all rival tribes within the Mongolian Steppe, except the Tartans. It was in the year 1206 that Genghis Khan was dubbed the undisputed leader of all the Mongolian tribes. It was during the Kuriltai or "great assembly" that Genghis Khan was given this postion. This was also when he changed his name from Temujin to Genghis Khan, meaning either "Oceanic Ruler" or "Strong Ruler". As soon as Genghis Khan became the sole leader of the area he immediately began uniting the people of different tribes, making an army, and designing a written language. These immediate tasks preserved Genghis Khan's rule that would last for the next twenty years. The National Geographic Article was perhaps my best source on Genghis Khan as it gave excellent details in a timeline and in paragraph form on Genghis Khan's rise. It also provided information on how Genghis Khan preserved his power in important battles. The National Geographic Article made it clear to me that Genghis Khan obtained power because of his control over his army, and how he designed his empire immediately after he gained power.

Sources for Alexander the Great:
http://encyclopedia.com/html/section/alexgreat_youthandkingship.asp
Unlike Genghis Khan, Alexander the Great did come to empowerment thanks to succession. His father, Philip II was the King of Macedonia before him. Once King Philip II passed away Alexander automatically became the new King of Macedonia. Immediately after the death of King Philip II Alexander was blamed for the death of his father. Citizens thought that Alexander was power hungry and killed his father to gain the throne. This theory was later disproved though. Since Alexander became king at such a young age people did not take him seriously. Because of this Alexander had to prove himself to the people of Macadonia, in order to gain their acceptance as King. The young Alexander did this by forcefully halting revolts in Thrace and Illyria. This show of leadership and power made the citizens realize Alexanders power, in turn, they respected him. Alexander went of to become on of Macedonia's most powerful leaders. This online encyclopedia gave a brief, but informative section on Alexanders youth and how he came to power. I did not need to infer anything about Alexander because the source stated facts exactly on Alexander's rise to power

http://www.e-classics.com/
Alexander the Great was a man born with a passion for fame. Alexander knew he was going to become the almighty King of Macedonia, however, it was not the particular power of the position that he wanted. Instead, Alexander simply wanted to become a great part of history by conquering different peoples and gaining the empire land. Alexander often got angry when his father completed conquests because it meant less land for him to conquer during his future reign. Alexander began making detailed plans for his empire at an early age. He wanted a powerful empire that was involved in violence, conquering, and a huge expansion. King Philip knew early in Alexander’s life that he was going to be an excellent ruler for Macedonia. Alexander had excellent leadership ability, wisdom, and the courage needed to rule such an immense area. King Philip even said to his son, "Oh my son, find yourself a kingdom worthy of yourself, Macedonia is too little for you." Alexander had his first opportunity to see what ruling an empire was like when he was only 16, when his father left Macedonia in his command while he went away on a campaign. Alexander faired well in his initial leadership role. It was only 4 years later that Alexander became the true King of Macedonia, inheriting it from his murdered father. Since Alexander was a young, and inexperienced leader many cities took this opportunity to rebel against him. Wanting to show no weakness in the early stages of his rule Alexander put down an iron fist and successfully thwarted the rebellions. This was a crucial part of Alexander the Greats rule because it showed the people what kind of power he had. Alexander continued to rule cruelly, and with an iron fist, but only when he had to. Other times he was forgiving and kind. These traits brought Alexander to extreme power over the next years. This primary source written by Plutarch was very useful. I found it very informative as it gave clear information on Alexander’s rise to power and childhood and gave a first hand account on it all. Plutarch happened to live during the time of Alexander so without doubt what he has written about Alexander's rise is correct.

http://ancienthistory.about.com/gi/dynamic/offsite.htm?site=http%3A%2F%2Fwww.bbk.ac.uk%2Fhca%2Fclassics%2Falexsources.htm
Alexander was a bright child and was brought up as the heir to throne. Knowing that his son was going to eventually become King of Macedonia, King Philip II had Alexander tutored by the great Aristotle. Aristotle gave Alexander perhaps the best education you could receive at the time and also supplied him with many of his morals. Alexander was allowed to rule Macedonia for a short period of time during his father’s trips to Byzantium. Alexander enjoyed this position of power and proved to handle the position well. In 336 BC King Philip II was murdered, and Alexander, who was almost twenty years became King of Macedonia. Although Alexander was not accepted immediately because of his age, and because he had feelings for the same sex, he did establish supreme power over his people. Alexander gained power simply by becoming the single conqueror of much of the free world. This primary source in particular gave many new views on Alexander. For example I did not know that Alexander was not accepted because he had an attraction to other males. This source also gave other useful background information from a first hand account. Although it did not go into great detail exactly on Alexander's rise one can infer based on what is said that Alexander's excellent education, provided by Aristotle, and his royal background was what helped contribute to Alexander's success in the long run, as well as his immediate rise to power.

http://ancienthistory.about.com/library/prm/blalexandersfirstgreatvictory.htm
In the year 336 B.C. King Philip II of Macedonia died. His son, Alexander became the new King of Macedonia. Not only did Alexander inherit the position of king, but also the greatest army of his time. Alexander would use this army to gain the maximum amount of power throughout his rule. Alexander was only twenty years old when he became the King of Macedonia. Many cities in Greece and Barbarians did not respect him because of his age. Upon hearing of King Philip II's death these cities and tribes revolted against the empire of Alexander. Outraged by this, Alexander did not hesitate to use his army for the first time. It took only two years for Alexander to regain internal peace within his empire, and also to gain himself respect from the people, and power. Internal power is not all Alexander wanted though. He also wanted to carry out his father’s dream of conquering Persia. During the Battle of Granicus Alexander did just that. This battle left Persian forces severely damaged and allowed Alexander to take them over. The conquering of Persia extended the Macedonian empire to its largest point, and gave Alexander the most power he would ever acquire in his life. This was by far the most useful source I have found on Alexander the Great. It goes into details on the Battle of Granicus and on how much power it gave Alexander. It also gives the details of his early power, and struggle to gain internal peace in his empire. None of the other sources have given all of these pieces of information.