Question: Who was the leader of the Autobots voiced by?
Context: The Autobots (also known as Cybertrons in Japan) are the heroes in the "Transformers toyline" and related spin-off comics and cartoons.  Their main leader is Optimus Prime, but other "Primes" have also commanded the Autobots such as Rodimus Prime.  They are constantly at war with the Decepticons.  In the U.S. cartoon line, the Autobots were the descendants of a line of robots created as consumer goods by the Quintessons; the Decepticons, are descended instead from robots designed as military hardware. Optimus Prime is a fictional character from the "Transformers" franchise.  He is the leader of the Autobots.  A fictional group of sentient robots that can transform into other forms (e.g: cars and other objects) He is the most iconic of the Transformers, being frequently featured in Popular Culture. Soundwave is the name of a fictional character appearing in various "Transformers" franchises.  His most famous transformation is that of a microcassette recorder.  Throughout most of his incarnations, he is an undying loyal lieutenant of the Decepticon leader Megatron.  He is Megatron's eyes and ears and, in some interpretations, only speaks when mocking the Autobots. Transformers: Prime is an American computer-animated television series based on the "Transformers" toy franchise by Hasbro that aired on Hub Network from November 29, 2010 to July 26, 2013.  The series was followed by a TV movie, "", which premiered on October 4, 2013 and concluded the show's story.  "Transformers: Prime" focuses on the heroic Autobots that make up "Team Prime", which consists of Optimus Prime, Ratchet, Arcee, Bumblebee and Bulkhead.  Throughout their battles, the Autobots are aided by three human children and with their help attempt to protect the Earth from the villainous Decepticons and their leader Megatron. This is a List of Primes and Matrix holders in the "Transformers" universe.  "Prime" is a fictional rank in the Transformers toy and entertainment franchise created by Hasbro and Takara Tomy.  The title is usually given to the leader of the Autobots and bearer of the Matrix of Leadership though there are a few exceptions, the most notable of these was in "Transformers Animated", where Prime was not a title, but a commanding rank amongst the Autobots, as indicated by Optimus to Sentinel, and second only to that of Magnus.  In Japanese translations of Western Transformers fiction, as well as original Japanese fiction such as "Beast Wars II", the equivalent to the Prime rank is "Convoy".  For example, "Rodimus Prime" would translate as "Rodimus Convoy" in Japanese, while "Lio Convoy" would translate as "Leo Prime" in English. Sentinel Prime is the name of several fictional characters in the various "Transformers" series.  First mention of Sentinel Prime was in issue #65 of the US Marvel Comics "Transformers" series, where he was mentioned to hold the Autobot Matrix of Leadership before Optimus Prime.  Sentinel Prime is One of the members of the Dynasty of Primes and dedicated as the leader of the Autobots and has since appeared in a variety of forms as either Optimus Prime's mentor or friend.  Fun Publications has also had a character in their comic called Sentinel Major, who is based on the "Transformers Animated" version of Sentinel Prime.  He is also the main antagonist in the film "," where he betrays the Autobots and later Megatron for his own personal interests.  His original "Generation 1" incarnation was later reimagined by IDW Publishing as a similar fallen figure, perhaps in lieu of his movie counterpart. Transformers is a 2007 American science fiction action film based on the toy line of the same name created by Hasbro.  The film, which combines computer animation with live-action filming, was directed by Michael Bay, with Steven Spielberg serving as executive producer.  It was produced by Don Murphy and Tom DeSanto, and is the first installment in the live-action "Transformers" film series.  The film stars Shia LaBeouf as Sam Witwicky, a teenager who gets caught up in a war between the heroic Autobots and the villainous Decepticons, two factions of alien robots who can disguise themselves by transforming into everyday machinery, primarily vehicles.  The Autobots intend to use the AllSpark, the object that created their robotic race, to rebuild their home planet Cybertron and end the war, while the Decepticons have the intention of using it to build an army by giving life to the machines of Earth.  Tyrese Gibson, Josh Duhamel, Anthony Anderson, Megan Fox, Rachael Taylor, John Turturro, and Jon Voight also star, while voice actors Peter Cullen and Hugo Weaving voice Optimus Prime and Megatron respectively. Grimlock is the name of several fictional robot characters in the Transformers franchise.  He is usually portrayed as the immensely strong, power-mongering leader of the Dinobots, a small subfaction of Autobots that transform into dinosaurs.  In 2007, "USA Today" polled people as to which Transformer they want to appear in the in the "Transformers" film series; Grimlock came in tied for second with Devastator. Huffer is the name of four fictional characters from the Transformers series.  All are Autobots who turn into trucks.  Huffer was first introduced in 1984, and was voiced by John Stephenson in the animated series "The Transformers". Sludge is a fictional character in the Transformers franchise.  Sludge is a slow witted but powerful Dinobot.  Sludge's strength is considered to be second only to Grimlock's in the Dinobot faction.  Sludge also has the great power to shake the ground violently and make huge tremors when stomping around in his Brontosaurus mode, which is a good weapon for shaking up Decepticons. Sludge also was seen at times to shoot laser beams from his eyes and an energy weapon from his mouth.  Sludge's biggest weakness is his belief that the strongest Autobot should lead and not necessarily the smartest.  Another weakness of Sludge's is that he is depicted as being mentally slow.  He joined the Autobots in the cartoon and comics in their first year, but didn't have a toy until 1985.  The other members of the Dinobots are Slag, Snarl, Swoop, and their leader, Grimlock.
Answer: Peter Cullen and Hugo Weaving