Penny Halliwell

Penelope "Penny" Halliwell (née Johnson), also known as Grams to her family, was a powerful witch, a High Priestess of Good, and the grandmother of the Charmed Ones: Prue, Piper, Phoebe and Paige. She was born on June 23rd, 1930, in a hotel room in Boston to P. Johnson née Baxter and Gordon Johnson. Penny also had a brother named Gordon Johnson II and gave birth to her daughter, Patricia Halliwell, on April 5th, 1950.

Early life
According to the family tree, she was born on June 23, 1930, in Boston, Massachusetts. She was born in a hotel room to her parents Gordon Johnson and P. Baxter. According to the family tree she has a brother who was born in 1943, when she was 13 years old, although, the family tree has many errors, and the existance of Gordon Johnson II is highly debated as it is established multiple times that Wyatt Matthew Halliwell is the first male born into the Warren/Halliwell line in generations, especially by his sister, Penny. P. Baxter, also known as Priscilla, died in December 1970, when Penny was forty years old. As a descendant of Melinda Warren, she had the power of Telekinesis.

Early on, Penny became a very powerful and skillful witch. She learned to focus her telekinetic power, and created spells and potions on her very own. According to Penny herself, she wrote all the good spells in the Halliwell's Book of Shadows.

She married her first husband, Allen Halliwell, sometime in the late 1940s. Together they had a daughter, Patricia, who was born in 1950. In the mid-1960s, Penny and Allen became leaders in San Francisco's hippie community. They made plans to hold a "magical be-in" at the manor and tap into the power of the Nexus. What Penny didn't know was that her best friend, Robin, was really an evil witch who'd been planning to slaughter everyone at the "be-in" with her warlock boyfriend, Nigel. On the night of the be-in, Allen walked in on Robin chanting an evil spell, and Robin killed him with a fireball. Penny flew into a rage upon seeing the carnage, and killed Robin and Nigel in short order. As a result, she became a fierce demon/warlock slayer.

Later in life, she started her own coven with her closest friends and non-magical practitioners as members, including her college sorority sister Gail, who commented that she was "the most skillful witch any of them ever knew".

Wiccan Duties
Shortly before her death, feeling it was her duty to protect her girls, Penny created a potion to relinquish her granddaughters' powers. She believed it was not their destiny to live the life she and her daughter Patty led battling demons and the forces of evil and facing the many hardships they endured over the years. Whilst creating the potion, Penny and Patty discuss whether it is the right decision or not to relinquish the sisters' powers, Patty argued that it is not their choice to decide the destiny of her daughters'. Penny then placed the Book of Shadows in a trunk in the Attic of the Manor but before she could administer the potion, she had a heart attack and fell down the stairs, after which her granddaughter's rushed to her side.

She created most of the potions in the Book of Shadows. She battled such evil beings as the Woogyman.

Grams became known as a High Priestess of Good who binds a witch to her love through Handfasting. She was summoned from the dead to bind Leo and Piper in matrimony.

As Penny became the matriarch of the Halliwell/Warren family, she fell in love with the Necromancer. But she couldn't be with him because, though he truly did love her, he used her to get to the spirits of the Halliwell/Warren line. She later banished his spirit forever in 2003.

Telekinesis
Penny is an extremely skillful and powerful witch, like her ancestor, Melinda Warren. Though she and her granddaughter Prue shared the same power of telekinesis, she was far more skilled in using it, having learned how to focus it, and created spells and potions on her very own. One memorable feat she performed was when she mistook the future versions of her granddaughters for warlocks, and telekinetically expelled them from the manor. Prue had never demonstrated such fine-control over human-sized objects, although she may have been able to later, had she not been killed so young. At Piper's wedding, we see that Grams can still use this power as a ghost (although it was already assumed due to her flipping of the Book of Shadows pages), this comes in very handy in her incorporial state.

In episode Cheaper By The Coven, Penny, as a ghost, could summon Patty without a spell. Presumably, she used her telekinesis as summon base.

Love Life and Family
Penny married a total of four times (starting with Allen), and was engaged for a total of six times, but the relationships didn't work out, making her very cynical towards men. However, she admited that at least her first husband, Allen Halliwell, was a good man and was still friends with him until his death. Though at some point during her first marriage, she had a love affair with a demon known as the Necromancer, who subsequently attacked during her daughter Patty's Wiccaning. When Patty married Victor Bennett, Penny didn't allow her to take his last name, a tradition that will be followed by the Charmed Ones (all except Paige).

Penny witnessed the birth of her granddaughters Prudence, Piper, and Phoebe Halliwell, later earning the nickname 'Grams'. When Patty was forced to give a warlock named Nicholas immunity to the girls' powers, Grams had no choice but to bind the girls' powers for their protection.

She was forced to keep the secret about the birth of Patty's fourth daughter Paige from everyone, because Paige was fathered by Patty's Whitelighter, Sam Wilder; relationships between witches and Whitelighters were then still forbidden by the Elders. Penny helped Patty and Sam decide that it was best to give the baby up for adoption. After Patty's death in 1978, Penny became surrogate mother to Patty's first three children, and would continually argue with Victor about how the girls should be raised. Because of their conflicting views, Victor eventually left his family: the girls didn't see their father again for almost 20 years. Penny was essentially a single mother from then on. .

When Paige was hesitant to accept the fact Penny was another one of her grandmothers, Penny talked Paige into opening her heart and letting herself into it; as she was not trying to replace any of the other family members Paige has loved or lost over the years.

Grams had long believed that her granddaughters would grow up to become the Charmed Ones. However, as the girls got older, she was increasingly worried about their constant bickering, and doubted they'd ever come together long enough to fulfill their destiny. Eventually, she decided to create a potion to permanently strip them of their powers. On March 5, 1998 she made the decision to give the sisters the potion, but before she could she had a heart attack and fell down the attic stairs to her death; she'd had a heart condition for several years.

She became a Guardian Spirit and High Priestess, keeping watch over her grandchildren and helping them find spells in the Book of Shadows. It is revealed in the premiere of season two, Witch Trial, that she is the one who turns pages for the girls when they're in a jam. She also reappears to bless her great-grandchildren at their Wiccanings.

In addition a future version (to her) of Piper and her husband Leo and a past version of Patty approached her for help. She was so shocked she fainted as Patty was dead at that time, but when she learned her granddaughters were the Charmed Ones, she immediately offered her help. Traveling to the present with the rest of the group, she, Piper and Patty made an impromptu Power of Three and removed the Hollow from Phoebe, Paige, Past Piper, Billy and Christie, changing the future. She witnessed Piper and Billie's future selves merge with their past selves and the disappearance of Leo. Later, after witnessing Future Wyatt and Chris, she traveled to Phoebe's loft and helped to make the potion that would ultimately vanquish the Triad. After a big family reunion, she and Patty are returned to their times by Coop and her memory of the event is erased despite her wish to remember.

Afterlife
Grams, as a high priestess, performed the marriage ceremony uniting Leo Wyatt and Piper in spirit form. When their first child turned out to be a boy, Grams was initially upset about it as she believed the family line should only be female, but eventually came around to accept and love her new great-grandson Wyatt. She told the girls that he looked like their grandfather Allen, which she said was a good thing as Allen was a good man.

When Grams learned about Gideon's death at Leo's hands (because Gideon had tried to kill Wyatt), she was unsure if she could trust Leo to be around the girls. She later learned to trust her family to make the right decisions without her input, but still provided them with assistance when needed.

Trivia

 * Kaley Cuoco, who portrays Billie Jenkins in Charmed's eighth season, is currently portraying a main character in a sitcom called The Big Bang Theory named Penny.
 * Grams being born in Boston could have been a nod to the fact that during the series' original conception, the Halliwells were all roommates in Boston.