He's actually only about 120 (not including his human years, which vampires don't seem to count toward their ages). We see in Fool For Love that he's turned in London in 1880 by Drusilla.
But the actor who played Spike, James Marsters, was actually 35 years old when he started on the show — 15 years older than Sarah Michelle Gellar, who played Buffy.
How old is Angel/Spike/Drusilla/Darla? Their sirings are all shown in flashbacks: Angel was turned in 1753, Spike in 1880, Drusilla in 1860, and Darla in 1609. Angel is 26, Drusilla is 19.
Kakistos was an old vampire whose hands and feet had turned cloven. Its Greek name meant "the worst." After killing Faith's first Watcher, Kakistos sought the Slayer in Sunnydale to avenge the scarring she left on him.
Spike (born William Pratt) was a famous and widely-feared vampire turned in 1880. He was well-known among both humans and demons for having faced and killed two Slayers during his unlife, as well as his history of torturing his victims with railroad spikes.
Darla attempted to turn Angel against the Slayer, and to bring him back to their side, but she failed, and Angel killed her.
Angel is stronger. Spike probably has a slight edge in speed, and possibly in skill because Angel spent many years moping around and not training, but it's usually not enough to counter Angel's superior strength.
1. Spike. We know that Team Angel fans are probably screaming at their computers right now, but hear us out. There are plenty of reasons Spike was the most powerful vampire in the Buffyverse.
Slayers are usually called at about fifteen years old, and Faith was called approximately two years after Buffy. Buffy also called Faith her "little sister slayer" or something along those lines. And the next point doesn't matter much in the world of acting, but Sarah Michelle Gellar is older than Eliza Dushku.
Spike Was Devoted To Drusilla
There's no mistaking the obvious devotion and personal care which led Spike to look after Drusilla for over a century. His attachment to her obviously stemmed from being sired by her in 1880, something Spike saw as a gift, making him see Dru as his savior.
After a visit from her ex-boyfriend Riley, Buffy broke off their relationship, and told him that she couldn't love him and was only using him to "feel alive." Buffy admitted that while she did have feelings for Spike, she did not love him, and told him that their relationship couldn't have been real to him because ...
Flashbacks in "Fool for Love" (season 5) show that Spike was sired as an adult in 1880. Assuming he was in his early to mid 20s when he was sired, Spike would be in his 140s during the series.
Buffy – a young woman whose mystical powers allowed her to battle evil forces – dated Angel during the show's first three series, before she ultimately chose vampire and initial villain Spike (James Marsters) to be her partner.
Born on January 19, 1981, she was called to be the Slayer in 1996 at fifteen years old.
1 Tara Maclay
She's an integral part of Buffy's middle seasons, and arguably stands as the show's most likable character, thanks to being impossible to dislike.
However, Faith Lehane (Eliza Dushku) eventually proves herself as the second most powerful Slayer after Buffy.
In the episode "Waiting in the Wings", Angel realizes he has romantic feelings for Cordelia, but is prevented from voicing them by the return of Groosalugg. Cordelia dates Groosalugg for the remainder of the season, but Groo notices she loves Angel instead and decides to leave.
In furious disbelief, Buffy assaults Spike and they battle until Buffy unleashes her desire and kisses him, initiating such passionate sex that the abandoned house in which they were fighting collapses around them.
Buffy treats him badly because she has no idea how else to deal with him. She is struggling to figure out her own feelings toward him while reeling over the fact that he is so obsessed with her that he would get his soul back.
Buffy: “The hardest thing in this world is to live in it. Be brave. Live.”
The Slayer line
However, because of the violent nature of the life of a Slayer, their average lifespan was quite short after being called, under a year at most. Consequently, the Shadowmen's spell also created a large number of Potential Slayers — common girls around the world who may one day be called.