The C1-C6 Spectrum after Fifteen Years

by John Jay Travis

The C-Spectrum has been used widely in mission circles and literature over the past fifteen years to differentiate various types of Christ-centered communities (biblical ekklesiae) found in the Muslim world.


Friends recently asked my wife and I how we became involved in outreach among Muslims and about the origins of the C1–C6 Spectrum (see Travis 1998, 407-408). We shared with them our personal journeys. 

I explained that in the 1970s I had the privilege of living with a Muslim family in Asia as a university student. I was a nominal Christian at the time. Some years later, when I was a committed follower of Jesus, my wife and I moved to that same Muslim country, spending a month with the family with whom I had previously lived. We ended up living for more than twenty years in that country and raising our own family there—all the while sharing the good news of Jesus with Muslim neighbors and friends. 

Regarding the C1–C6 Spectrum, I explained that it was my attempt to describe six types of fellowships that I had seen people who were born Muslim either form or join after they began to follow Jesus. Each type of fellowship I referred to as a different form of Christ-centered community (hence the letter C in the Spectrum). I had not initially planned to publish the C-Spectrum, and only did so when some who knew of it were objecting to certain types of fellowships it describes (see Parshall 1998, 404-410; Travis 1998, 411-415). 

I explained that the C-Spectrum was primarily descriptive. I had hoped it would increase awareness among cross-cultural workers of various ways God was moving among Muslims. I had also hoped it would bring greater unity and mutual respect among workers who were using different ministry approaches but who had the same goal of seeing God’s kingdom grow. I mentioned to our friends some of the limitations I saw in the C-Spectrum as well.

After hearing our story, our friends felt that the C-Spectrum had often been misunderstood or misused and that it would be good to write an article explaining its intended use and limitations. This article is my response to their suggestion.

Use and Description of the C-Spectrum

The C-Spectrum has been used widely in mission circles and literature over the past fifteen years to differentiate various types of Christ-centered communities (biblical ekklesiae) found in the Muslim world. It has been adapted for use in other socioreligious contexts such as Hindu and Buddhist-background fellowships as well. Additionally, it has been alluded to in reference to the postmodern West (Frost and Hirsch 2003). 

The C-Spectrum is framed around two central issues: (1) the socioreligious identity of fellowships of Jesus-followers who were born Muslim and (2) the linguistic, cultural, and religious forms they use. It is assumed that each of these types of Christ-centered communities follows Jesus as the risen Lord and Savior and the Bible as God’s word. Any group along the C-Spectrum could, however, become sub-biblical if adherence to scripture becomes weak. The following is a brief description of the six basic types of Christ-centered communities.

The first type of Christ-centered community, which I called C1, refers to churches in the Muslim world that use distinctly non-Muslim, “Christian” forms (music, liturgy, architecture, prayer posture, etc.) and hold their worship services in languages other than the mother tongue of the surrounding Muslim population. Thousands of these churches exist in the Middle East, Asia, and Africa, some of them predating Islam (e.g., Eastern Orthodox and Armenian churches).

C2 refers to churches similar to C1, except that the worship is conducted in the mother tongue of the surrounding Muslim population. However, although they use the daily language of the local Muslim population in worship, they seldom use the same religious terms as local Muslims—such as Isa for Jesus, Yahya for John the Baptist, or Zabur for Psalms. In terms of socioreligious identity, the central issue of the C-Spectrum, members of C1 and C2 fellowships refer to themselves as Christians or by the name of their denomination/church (e.g., Orthodox, Catholic, or Coptic). Muslim-background believers are found in various C2 congregations or in specialized subgroups associated with them.

C3 refers to fellowships that incorporate local or indigenous ethnic and cultural forms such as music, dress, and artwork rather than distinctively Western or Christian ones. C3 groups thus aim to develop indigenous expressions of congregational life while avoiding forms that appear “Islamic.” An underlying assumption of C3 groups, therefore, is that “cultural” and “Islamic” forms can be separated in Muslim societies. C3 groups would typically avoid using Muslim terminology. As with C1 and C2 communities, C3 groups refer to themselves as Christian. 

The fourth type, C4, differs from C3 in that instead of avoiding Islamic forms (religious terminology, holidays, personal names, diet, dress, prayer posture, etc.), these groups retain them, filling them where necessary with new biblical meaning. In general, they avoid the label “Christian” due to the unfortunate cultural baggage it carries.1 C4 groups tend to refer to themselves as “followers of Isa” or in other, similar terms that focus on Jesus and allegiance to him. 

The fifth type of Christ-centered community, C5, consists of groups of Muslims who follow Jesus as Lord and Savior and the Bible as God’s word without taking the step of leaving the religious community of their birth. Some C5 groups relate with Christian-background believers for friendship and spiritual interaction, but they form and lead their own groups (ekklesiae) for prayer, fellowship, and Bible study. By remaining part of the Muslim community, they are a source of salt and light for family and friends. 

The C-Spectrum does not attempt to describe C5 in terms of linguistic, cultural, and religious forms, as there is too much variance worldwide to discern a common pattern. As a general category of the C-Spectrum, what makes a C5 type of group distinct is maintaining a Muslim socioreligious identity. In other words, they integrate the practice of their biblical faith in Jesus into their everyday life in the religious community of their birth. A “C5 movement” would therefore be synonymous with an insider movement. I know of C5 group members who refer to themselves with various descriptions such as “Holy Spirit Muslims,” “Muslim believers,” “Muslim followers of Jesus,” or simply “Muslims.”

Finally, C6 refers to the many small and scattered groups of Jesus followers who are underground, isolated, or restricted in their ability to meet. Their context limits their ability to gather openly and makes public witness difficult, yet many find creative ways to connect with other Jesus-followers and share the good news discreetly as God’s Spirit leads. Similar to C5, these Jesus-followers retain their Muslim identity as they follow Jesus as Lord and Savior. As with C5, the C-Spectrum does not attempt to describe them in terms of linguistic, cultural, or religious forms.

Seven Common Misunderstandings and Misuses

Much has been written about these six general types of Jesus-centered communities since the C-Spectrum was first published in 1998. Some literature has been for or against various points along the C-Spectrum, with most of the discussion focused on C5. Other literature does not critique the types of fellowships per se, but rather discusses the strength or weakness of the model itself.

Some critiques have dealt squarely with what I have written and intended. Others, however, have been based on misunderstandings or misuses of the C-Spectrum. Below I address common misunderstandings and misuses, followed by my own critique of the C-Spectrum, where I point out some of its limitations and make suggestions for the future.

1. The first common misunderstanding has to do with what the letter C represents. It does not stand for “contextualization,” “cross-cultural church-planting spectrums,” or “Christian”—all terms that have been mistakenly used. It stands for “Christ-centered communities”; in other words, fellowships or groups of Jesus-followers—biblical ekklesiae

2. The C-Spectrum is meant to show how groups of Jesus-followers who were born Muslim express their faith, not how cross-cultural workers among Muslims express theirs. Unfortunately the first article critiquing the C-Spectrum (Parshall 1998) focused much of its attention on a few foreign field workers who had assumed a Muslim identity to reach Muslims. This actually has nothing whatsoever to do with the C-Spectrum, yet the idea of cross-cultural workers “becoming C5” keeps resurfacing in C-Spectrum discussions. 

3. No point along the C-Spectrum is intended to be better or more biblical than any other. Any expression of faith in Jesus along the C-Spectrum could be appropriate for a particular culture or group. Any group along the C-Spectrum could become sub-biblical if adherence to the Bible becomes weak. Some would argue that C1 or C2 types are more biblical or less prone to error than, say, C4 or C5. The reality of the situation does not bear this out. Some of the most nominal and sub-biblical groups fall into C1 or C2 categories. I was shocked recently to learn that, in one country, many cross-cultural workers had understood C6 to be the ideal because it was the highest number on the C-Spectrum! The reason for portraying these different types of fellowships along a flat, linear spectrum was to communicate that in God’s eyes all members of God’s kingdom are of equal value before him, regardless of their cultural or socioreligious labels. 

4. The C-Spectrum is not intended to be exhaustive. It highlights six types of fellowships, but other expressions or variations are entirely possible. When I used the word “spectrum” I had in mind a range of colors placed side by side, with theoretically infinite shades between them. Many have understood this, often describing a particular fellowship as being between or similar to some point on the C-Spectrum (e.g., “between C2 and C3” or “like C4 but…”). For some, however, there has been misunderstanding when they could not find a direct correlation between a type of fellowship they knew of and one of the six basic C-Spectrum descriptions.

5. Points along the C-Spectrum are not to be seen as static or unchangeable. Over time, a fellowship could change, taking on a different socioreligious identity from what it held previously. C-Spectrum descriptions are only snapshots of the moment and do not reflect change or direction.

6. The C-Spectrum was designed to describe groups, not individual Jesus-followers. This is an easy mistake to make (I have done it myself), since fellowships are made up of individuals who presumably reflect the characteristics of the group. It is therefore quite natural to refer to someone as a C4 believer, meaning that person displays the characteristics and socioreligious identity associated with a C4 group. However, this has caused some to misunderstand the model since individual Muslim-background believers they know do not fit perfectly into any particular point along the C-Spectrum. 

In practice, many have noted that individual Jesus followers have two or three different types of identity used in different social contexts. It is my opinion that groups, on the other hand, are more likely to have a single identity as they negotiate who they are collectively with the larger community. It may be possible, however, that groups also have more than one identity, which would show a limitation in the use of the C-Spectrum. Individuals, in fact, may have more than one socioreligious identity. For example, a Muslim-background believers group may be linked to a C2 church, clearly C2 in its identity and forms. Yet in certain situations, individual members may still identify with the Muslim community, even at times feeling culturally or socially Muslim themselves. Additional, more detailed, models are needed to bring out nuances such as dual or multiple identities.

7. The greatest misuse of the C-Spectrum is the way some have added to or redefined the meaning of C5 to include Islamic practices and beliefs that they assume Jesus-following Muslims must be retaining. This has created a straw man that critics can then attack. The following are examples I have heard of altered descriptions or additions to C5 that clearly depart from my original definition: viewing Muhammad as on par with Jesus, viewing the Qur’an as having higher authority than the Bible, using only the Muslim holy book for discipleship, and forcing frequent mosque attendance. No C5 group I am acquainted with holds to any of the above beliefs or practices.

The reality on the ground is that as C5 groups engage the Bible under the guidance of the Spirit of God, they come to their own convictions about Muslim beliefs and practices. Some are rejected, some are reinterpreted, and those not in conflict with the Bible are generally continued. As serious disciples, they are learning how to navigate their new faith in Jesus in the midst of being part of the religious community of their birth. Because particulars of how this happens vary from group to group, the original description of C5 focused only on their allegiance to Jesus as Lord and Savior and the Bible as God’s word, and not on what they reject or retain from Islam. 

Limitations of the C-Spectrum

All models have limitations and can only approximate reality. I see two limitations in particular with the C-Spectrum. 

1. The first is in what it does not describe. It addresses language, culture, religious forms, and group identity, but does not describe intangibles such as the motivations, life experiences, or aspirations of those in the groups. Why do some groups of Jesus followers form or join C1 or C2 churches while others join or form C4 or C5 fellowships? Or what political, cultural, and legal factors and pressures might influence certain groups toward a C3 expression of faith but others toward C6—the latter becoming what some have described as “catacomb believers”?2 I am sure many of the criticisms people have for one or another expression of faith along the C-Spectrum would be greatly reduced if they could walk for a while in the shoes of others, understanding their hearts and life stories.

2. A second limitation is that this flat, linear model, while helpful in showing variety, can also be limiting if understood as portraying six distinct categories positioned side by side, without overlapping, sharing, or blending of characteristics. As many have noted when trying to use the one-dimensional C-Spectrum as a means of classification, some fellowships defy description and contain elements from a number of points along the C-Spectrum. 

Four Recommendations in Using the C-Spectrum

In spite of its limitations, the C-Spectrum is commonly used worldwide. I offer four recommendations for those who use it. 

1. It is best used among colleagues who have a clear and common understanding of what descriptions within the C-Spectrum mean. It can serve as a convenient nomenclature and starting point for discussion. To use it between different ministries and organizations, however, is risky due to the variety of ways in which one group or another understands it.

2. Because it can be misunderstood or misapplied, it is often more helpful, as long as appropriate security measures are set in place, to employ narrative and story when discussing ministry in Muslim contexts. Narratives, case studies, and longer descriptions, given by those actually on site and involved, help unpack some of the complexities of context (legal, political, and social) and can bring out the motivations, hopes, and life experiences of Jesus-followers. In addition, by avoiding C-Spectrum labels, the emotional baggage those terms carry for some can be eliminated so that parties can hear and not talk past each other.

3. Better graphics could avoid the appearance of rigidity and static categories that a one-dimensional graphic might communicate. (The original article on the C-Spectrum did not show any graphic—it only presented in a list the six basic types of fellowships.)

4. The effectiveness of the C-Spectrum would be greatly enhanced if augmented by other models and tools now being developed. 


The C-Spectrum has been commonly used as a heuristic tool to describe certain types of Christ-centered fellowships found in Muslim contexts. It focuses on the outward forms of some of these fellowships as well as their socioreligious identity. While helpful in some ways, the C-Spectrum has also been misunderstood or misused. 

Hopefully, future use of the C-Spectrum can be augmented by other models and descriptive tools. Narratives and case studies, with appropriate anonymity and safeguards, can bring out nuances and complexities that a spectrum or scale cannot. 

In the spirit of the original intent of the C-Spectrum, let us acknowledge the wide variety of expressions of life in the kingdom that groups of Jesus-followers choose. Since God’s wisdom and the creativity of his people will certainly yield still more variety in the years ahead, we would do well to rejoice in all that God does in the lives and families of Muslims, whom he loves.


1. Among Muslims, the terms “Christian” and “Christianity” often denote ethnic or political realities associated with Western peoples and cultures, including immoral Hollywood films, immodest dress, alcohol misuse, anti-Islamic sentiments, and certain political agendas. These terms are not generally used by Muslims to refer to someone who truly believes in Jesus and follows him any more than Christians use the term “Muslim” to mean “someone submitted to God.”

2. Father Jean-Marie Gaudeul (1999, 264-265, 288) coined the phrase “catacomb believers” to refer to Muslims who follow Jesus privately or underground, even as many early Christ followers did, meeting in the catacombs of ancient Rome. 


Frost, Michael and Alan Hirsch. 2003. The Shaping of Things to Come: Innovation and Mission for the 21st-Century Church. Peabody, Mass.: Hendrickson.

Gaudeul, Father Jean-Marie. 1999. Called from Islam to Christ: Why Muslims Become Christians. East Sussex, U.K.: Monarch.

Parshall, Phil. 1998. “Danger! New Directions in Contextualization.” Evangelical Missions Quarterly 34(4): 404–410.

Travis, John. 1998a. “The C1 to C6 Spectrum: A Practical Tool for Defining Six Types of ‘Christ-centered Communities’ (‘C’) Found in the Muslim Context.” Evangelical Missions Quarterly 34(4): 407–408.

_____. 1998b. “Must All Muslims Leave ‘Islam’ to Follow Jesus?” Evangelical Missions Quarterly 34(4): 411–415.  


John Jay Travis, PhD, is an affiliate assistant professor of intercultural studies at Fuller Theological Seminary and has lived most of his adult life in Asian Muslim communities. He has authored numerous articles and book chapters and is co-editor of Understanding Insider Movements: Disciples of Jesus in Diverse Religious Communities.

EMQ, Vol. 51, No. 4 pp. 358-365. Copyright  © 2015 Billy Graham Center for Evangelism.  All rights reserved. Not to be reproduced or copied in any form without written permission from EMQ editors.

Questions for Reflection

1. What was the author’s original hope for the C-Spectrum?

2. What insights have you gained about the C-Spectrum and its usage as a result of reading this article?




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