You’re staring at a mess of lines. Maybe it’s a printout from Ancestry.com or a dusty drawing from your Great Aunt's attic, but it basically looks like a subway map designed by someone who’s never seen a train. Most people think family history is just about names and dates. It's not. It’s about connections. But when those connections get messy—think second cousins twice removed or "double first cousins"—a standard family tree explanation chart becomes the only thing standing between you and total confusion.
I’ve spent years looking at these things. Honestly, they can be a nightmare if you don't know the "grammar" of the lines.
People often give up because they hit a wall. They see a dotted line and wonder if it means an adoption, an affair, or just a printer error. Usually, it's something specific. To really get what’s going on, you have to stop looking at the names and start looking at the geometry.
Why your family tree explanation chart feels like a foreign language
It’s all about the axes. Horizontal lines are your peers. Vertical lines are your legacy.
When you look at a family tree explanation chart, the most common mistake is assuming every line means the same thing. It doesn't. A solid line connecting two people horizontally usually indicates a legal marriage, but you’ll often see a "broken" horizontal line or a small "x" in more modern charts to signify a divorce or a separation. If you’re looking at European royal pedigrees, you might even see red lines for direct blood succession and blue for cadet branches. It gets complicated fast.
Think about the "removed" terminology. This is where everyone loses their mind.
Most people think "second cousin once removed" means your cousin’s kid. They’re right, but they can’t explain why. A "removal" just means you are in different generations. If you’re on the same horizontal plane of the chart, you’re full cousins. If you have to move up or down a level to find the other person, they are "removed." One level? Once removed. Two levels? Twice removed. It’s basically just genealogical math.
The anatomy of a relationship chart
You’ve probably seen those giant grid-style charts. They look like multiplication tables from third grade. On one side, you have "Relationship to Common Ancestor," and on the top, you have the same. You find the intersection point, and boom—you’re third cousins.
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But those grids are cold. They don't tell the story.
A real family tree explanation chart used by professional genealogists—the kind you’d see from the National Genealogical Society—uses specific numbering systems. The most famous is the Ahnentafel system. It’s a German word that basically means "ancestor table." It’s brilliant because it uses math to keep track of everyone. You are #1. Your father is #2. Your mother is #3. Your paternal grandfather is #4.
Notice a pattern?
Every father's number is double the child's number. Every mother's number is double the child's number plus one. It’s a perfect mathematical loop. If you see #64 on a chart, you instantly know that’s a great-great-great-great grandfather. No guessing. No tracing lines with your finger until your eyes hurt. It's just logic.
Those weird symbols you keep seeing
Sometimes charts use icons instead of words to save space. It’s shorthand.
- An asterisk (*): Usually denotes a birth date.
- A cross (†): This is the universal symbol for death in genealogy.
- The infinity symbol (∞): Sometimes used to show a marriage date.
- Two interlocking circles: Another way to show marriage, though it’s becoming less common in digital software like FamilySearch or MyHeritage.
If you see a dotted line descending from a couple to a child, that’s almost always the standard way to indicate an adoption. It shows the emotional and legal bond without claiming a biological "blood" link on a genetic chart. Speaking of genetics, DNA matches have changed how these charts look entirely. Now, you might see "centimorgans" (cM) written next to a name. That’s a measurement of how much DNA you actually share. If you see 3,400 cM, that’s a parent or a child. If you see 20 cM, you’re looking at a distant cousin who you probably wouldn't recognize at a grocery store.
The "Consanguinity" problem
Let's get into the stuff people usually whisper about. Consanguinity. It’s just a fancy word for "being related by blood."
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In some cultures and time periods, marrying a cousin wasn't just okay; it was preferred to keep land and wealth in the family. When this happens, your family tree explanation chart starts to look like a braid. This is called "pedigree collapse."
Normally, you have two parents, four grandparents, and eight great-grandparents. But if your great-grandparents were also cousins, you might only have six unique great-grandparents. The chart literally folds in on itself. This is why the Hapsburg royalty charts are so famous—and so medically tragic. When you trace their lines, you see the same names appearing on both the mother’s and father’s sides repeatedly. The chart stops being a tree and starts being a diamond.
Modern digital vs. old-school paper
Digital trees are great because they’re infinite. You can click a name and dive into a whole new branch. But they have a massive flaw: you lose the "big picture."
When you use a physical family tree explanation chart, you can see the clusters. You see how the Miller family stayed in the same county for 200 years, marrying into the Smith family five different times. You see the gaps where the 1918 flu pandemic wiped out an entire generation in three weeks.
Paper charts force you to be precise. You can't just "auto-hint" your way through a paper chart. You have to verify the link before you draw the line. Most amateur genealogists make the mistake of "click-collecting." They see a hint on a website, click "accept," and suddenly they’ve attached a 17th-century Duke to their family tree without a single shred of evidence. A physical chart makes you feel the weight of every line you draw.
The Fan Chart: A different perspective
If the standard "top-down" chart is too boring, look at a Fan Chart. It puts you in the center. Your parents are the two segments directly above you, and the chart fans out in a semicircle.
It’s the best way to see where your research is lacking. If the right side of the fan is full and colorful, but the left side is a giant white void, you know exactly where you need to spend your time. Usually, that void is a "brick wall"—a grandmother whose maiden name was never recorded or an immigrant ancestor whose ship manifest was lost.
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Practical steps for your own chart
If you’re serious about making one of these that actually makes sense to other people, you have to follow a few "unwritten" rules.
First, names. Always use maiden names for women. Always. If you put "Mary Smith" on a chart but Smith was her husband’s name, you’ve just erased her entire history. She becomes invisible to anyone trying to find her parents. Use her birth name so the line leads back to her father.
Second, dates. Use the "Day Month Year" format (e.g., 12 May 1944). It prevents confusion between American and European styles. Is 05/06/1944 May 6th or June 5th? If you write out the month, there’s no debate.
Third, location. A name without a place is just a ghost. "John Williams" is the most common name in Wales. If you just have "John Williams, born 1820," you’ll never find him. "John Williams, born 1820 in Llandudno, Caernarfonshire" is a real person you can track.
Common Misconceptions
People think a family tree has to go "up" or "down." Actually, "descendant charts" go down (starting with an old ancestor and showing everyone who came from them), while "pedigree charts" go up (starting with you and looking at your ancestors). Most people want a pedigree chart. They want to know where they came from. But if you’re planning a family reunion, you want a descendant chart so everyone can see how they’re related to the guest of honor.
Also, "Great-Uncle" vs. "Grand-Uncle." Technically, your grandfather’s brother is your grand-uncle. Most people say great-uncle. Both are usually accepted, but if you want to be a nerd about it, "grand" matches the "grandfather" generation.
How to use this for your research
Don't try to build the whole thing at once. You'll get overwhelmed and quit.
- Start with what you know. Fill in yourself, your parents, and your grandparents. Do not look at a single website yet. Just use your brain and your own documents.
- Interview the oldest person in your family. Ask them about the "empty" spots. Don't just ask for names; ask for stories. "Was there a brother who went to California and was never heard from again?" Those stories are the "dotted lines" that lead to breakthroughs.
- Choose your format. If you have a huge family, go for a "Horizontal Descendancy" chart. It spreads out wide and is easier to read on a wall. If you’re just tracking your direct bloodline, a "Standard Pedigree" chart is fine.
- Verify with primary sources. A birth certificate is a primary source. A story your drunk uncle told you at a BBQ is a "lead." Don't put a lead in permanent ink on your family tree explanation chart until you have the paper to back it up.
Genealogy is a puzzle that never ends. Every time you find an answer, it just creates two more questions. But having a solid chart keeps you grounded. It’s the map for the journey. Without it, you’re just wandering through a graveyard of names. With it, you’re piecing together a story that actually belongs to you.
Focus on the connections first, the names second, and the dates third. If you get the lines right, the rest of the history eventually falls into place. Use a pencil. You're going to make mistakes, and that's okay. Even the pros have to erase things when a DNA test proves a 100-year-old family legend was actually a cover-up. That's where the real fun starts anyway.