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Data

Years a country was an European overseas colony

See all data and research on:
State Capacity

About this data

Years a country was an European overseas colony
Number of years the country has been colonized from overseas by the European colonial power(s) in a specific year, between Belgium, United Kingdom, France, Germany, Netherlands, Portugal, Spain, and Italy, or a combination of them.
Source
Bastian Becker (2023) – with major processing by Our World in Data
Last updated
September 18, 2023
Next expected update
May 2026
Date range
1462–2022
Unit
years

Sources and processing

This data is based on the following sources

Bastian Becker – Colonial Dates Dataset (COLDAT)

The Colonial Dates Dataset (COLDAT) aggregates information on the reach and duration of European colonial empires from renowned secondary sources. By aggregating secondary sources, rather than collecting from primary sources, the new dataset reflects the accumulated knowledge in the discipline and relieves researchers from making hard to justify choices between different historical datasets. The dataset only considers the colonial status of countries that are independent today. It also includes overseas colonies only.

Retrieved on
September 22, 2023
Retrieved from
https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/T9SDEW
Citation
This is the citation of the original data obtained from the source, prior to any processing or adaptation by Our World in Data. To cite data downloaded from this page, please use the suggested citation given in Reuse This Work below.
Becker, Bastian (2019), Introducing COLDAT: The Colonial Dates Dataset, SOCIUM/SFB1342 Working Paper Series, 02/2019. url: https://www.socium.uni-bremen.de/f/51ebd445c4.pdf

The Colonial Dates Dataset (COLDAT) aggregates information on the reach and duration of European colonial empires from renowned secondary sources. By aggregating secondary sources, rather than collecting from primary sources, the new dataset reflects the accumulated knowledge in the discipline and relieves researchers from making hard to justify choices between different historical datasets. The dataset only considers the colonial status of countries that are independent today. It also includes overseas colonies only.

Retrieved on
September 22, 2023
Retrieved from
https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/T9SDEW
Citation
This is the citation of the original data obtained from the source, prior to any processing or adaptation by Our World in Data. To cite data downloaded from this page, please use the suggested citation given in Reuse This Work below.
Becker, Bastian (2019), Introducing COLDAT: The Colonial Dates Dataset, SOCIUM/SFB1342 Working Paper Series, 02/2019. url: https://www.socium.uni-bremen.de/f/51ebd445c4.pdf

How we process data at Our World in Data

All data and visualizations on Our World in Data rely on data sourced from one or several original data providers. Preparing this original data involves several processing steps. Depending on the data, this can include standardizing country names and world region definitions, converting units, calculating derived indicators such as per capita measures, as well as adding or adapting metadata such as the name or the description given to an indicator.

At the link below you can find a detailed description of the structure of our data pipeline, including links to all the code used to prepare data across Our World in Data.

Read about our data pipeline
Notes on our processing step for this indicator

This is a cumulative sum of the years the country has been colonized, across the entire time series. Colonizers or countries not colonized show a value of 0.

Years are defined from last date aggregations available in the Colonial Dates Dataset. This means that when sources differ, years of colonization are defined from the last date between them. This is different from mean date aggregations (also available), which averages the dates of colonization across the original sources.

Years have been expanded to show the full range of years in the dataset, from 1462 to 2022. The original dataset only includes the years where a country was colonized.

Reuse this work

  • All data produced by third-party providers and made available by Our World in Data are subject to the license terms from the original providers. Our work would not be possible without the data providers we rely on, so we ask you to always cite them appropriately (see below). This is crucial to allow data providers to continue doing their work, enhancing, maintaining and updating valuable data.
  • All data, visualizations, and code produced by Our World in Data are completely open access under the Creative Commons BY license. You have the permission to use, distribute, and reproduce these in any medium, provided the source and authors are credited.

Citations

How to cite this page

To cite this page overall, including any descriptions, FAQs or explanations of the data authored by Our World in Data, please use the following citation:

“Data Page: Years a country was an European overseas colony”, part of the following publication: Bastian Herre and Pablo Arriagada (2023) - “State Capacity”. Data adapted from Bastian Becker. Retrieved from https://archive.ourworldindata.org/20260325-171315/grapher/years-colonized.html [online resource] (archived on March 25, 2026).

How to cite this data

In-line citationIf you have limited space (e.g. in data visualizations), you can use this abbreviated in-line citation:

Bastian Becker (2023) – with major processing by Our World in Data

Full citation

Bastian Becker (2023) – with major processing by Our World in Data. “Years a country was an European overseas colony” [dataset]. Bastian Becker, “Colonial Dates Dataset (COLDAT) 3.0” [original data]. Retrieved April 1, 2026 from https://archive.ourworldindata.org/20260325-171315/grapher/years-colonized.html (archived on March 25, 2026).

Download

Quick download

Download the data shown in this chart as a ZIP file containing a CSV file, metadata in JSON format, and a README. The CSV file can be opened in Excel, Google Sheets, and other data analysis tools.

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Data API

Use these URLs to programmatically access this chart's data and configure your requests with the options below. Our documentation provides more information on how to use the API, and you can find a few code examples below.

Data URL (CSV format)
https://ourworldindata.org/grapher/years-colonized.csv?v=1&csvType=full&useColumnShortNames=false
Metadata URL (JSON format)
https://ourworldindata.org/grapher/years-colonized.metadata.json?v=1&csvType=full&useColumnShortNames=false

Code examples

Examples of how to load this data into different data analysis tools.

Excel / Google Sheets
=IMPORTDATA("https://ourworldindata.org/grapher/years-colonized.csv?v=1&csvType=full&useColumnShortNames=false")
Python with Pandas
import pandas as pd
import requests

# Fetch the data.
df = pd.read_csv("https://ourworldindata.org/grapher/years-colonized.csv?v=1&csvType=full&useColumnShortNames=false", storage_options = {'User-Agent': 'Our World In Data data fetch/1.0'})

# Fetch the metadata
metadata = requests.get("https://ourworldindata.org/grapher/years-colonized.metadata.json?v=1&csvType=full&useColumnShortNames=false").json()
R
library(jsonlite)

# Fetch the data
df <- read.csv("https://ourworldindata.org/grapher/years-colonized.csv?v=1&csvType=full&useColumnShortNames=false")

# Fetch the metadata
metadata <- fromJSON("https://ourworldindata.org/grapher/years-colonized.metadata.json?v=1&csvType=full&useColumnShortNames=false")
Stata
import delimited "https://ourworldindata.org/grapher/years-colonized.csv?v=1&csvType=full&useColumnShortNames=false", encoding("utf-8") clear