A short diagram of Britain's royal family includes information from the reign of Alfred the Great, who ruled from 849 to 899, through the monarch as of 2015, Queen Elizabeth II, who was born in 1926. All monarchs are shown in such a tree, along with their siblings and heirs.
Some shortened trees show each monarch's spouse or spouses and his or her recognized, or legitimate, children. Because of this type of tree's condensed nature, those in the family who are not the child or spouse of a monarch are not included, such as a monarch's cousins. A slightly less condensed family tree features the family trees of all British dynasties, including those of the past, such as the Plantagenets, Yorks, Lancastrians, Tudors, Stuarts, Hanoverians and the Saxe-Coburg-Gothas, and the present family, the Windsors.
For researchers interested in the most basic outline of information about Britain's kings and queens, listing all monarchs chronologically and arranging them by their houses of origin is a good option. YouTube offers a good visualization of the British monarchs with the video "British Royal Family Tree," which takes viewers from William the Conqueror, whose rule began in 1066, through the birth of Prince George of Cambridge, who was born in July 2013.